WO2009121149A1

WO2009121149A1 - Stabilized photochromic

Info

Publication number: WO2009121149A1
Application number: PCT/AU2009/000418
Authority: WO
Inventors: Nino Malic; Richard Alexander Evans
Original assignee: Advanced Polymerik Pty Ltd
Priority date: 2008-04-03
Filing date: 2009-04-03
Publication date: 2009-10-08

Abstract

There is provided a photochromic polymer for use in a polymeric composition comprising at least one photochromic moiety and at least one substituent comprising a gas barrier polymer selected from the group consisting of polymers of vinyl monomers of chemical formula CH₂=CXY wherein at least one of X and Y is selected from the group consisting of hydroxyl, acetyl, nitrile and chlorine and the other is selected from the group consisting of hydrogen and chlorine and copolymers of said monomer; polyesters and copolymers thereof; and polyamides and copolymers thereof.

Description

STABILIZED PHOTOCHROMIC

Field

[0001] The invention relates to photochromic polymers and compositions and in particular to photochromic polymers and compositions which are more resistant to photochromic fatigue.

Background

[0002] A drawback to the widespread commercial use of organic photochromic compounds is the loss of their ability to change colour as a result of prolonged repeated exposure to U. V. light, that is, the organic photochromic compounds lose their photochromism or their ability to change colour and revert to their original colourless state. The phenomenon is believed to be a result of irreversible decomposition of the organic photochromic compound and is referred to as fatigue or light fatigue.

[0003] It has been suggested that the light fatigue resistance of spiro(indoline)naphthoxazine compounds may be increased by their use in a host material which contains a hindered amine light stabilizer (HALS) and optionally a complex of the nickel ion with an organic ligand as a singlet oxygen quencher.

Summary

[0004] We have found that fatigue resistance is substantially improved by use of substituents which provide a barrier to the passage of oxygen reaching the photochromic moiety.

[0005] In accordance with the invention we provide a photochromic polymer comprising a photochromic moiety and at least one substituent comprising a gas barrier moiety.

[0006] The at least one substituent preferably comprises a gas barrier polymer. The at least one substituent comprising a gas barrier polymer provides passive protection of the photochromic moiety. The gas barrier polymeric moiety may be covalently bonded directly to the photochromic material or may be linked by one or more linking groups and/or other polymer groups.

[0007] Gas barrier polymers may be selected from step growth and chain growth polymers that are known to provide good barrier properties towards preferably oxygen and/or water. Chain growth polymers made from free radical polymerization that are typical good barrier polymers are those that contain repeat units derived from the polymerization of monomers containing cyano or chloro groups. Non-limiting examples of such monomers are acrylonitrile, methacrylonitrile, vinylchloride, vinylidene chloride, vinyl alcohol. Such monomers are frequently copolymerized with other monomers like butyl acrylate to enable greater processability of the barrier polymer although this is not essential for the current invention. Further examples of barrier polymers include fatty aliphatic (preferably unsaturated fatty aliphatic), polyesters and polyamides.

[0008] The invention provides a photochromic polymer for use in a polymeric composition the photochromic polymer comprising at least one photochromic moiety and at least one substituent comprising a gas barrier polymer selected from the group consisting of polymers of vinyl monomers of chemical formula CH₂=CXY wherein at least one of X and Y is selected from the group consisting of hydroxyl, acetyl, nitrile and chlorine and the other is selected from the group consisting of hydrogen and chlorine and copolymers of said monomer; polyesters and copolymers thereof; and polyamides and copolymers thereof.

[0009] In a preferred embodiment of the invention the photochromic compound further comprises a low Tg polymeric chain so that the rate of fade of the photochromic is significantly increased. In this embodiment the low Tg polymer may be disposed between the gas barrier polymer and photochromic moiety, may be a separate substituent on the photochromic, may be bonded to the gas barrier polymeric moiety remotely from the photochromic or may be linked to the same substituent as the gas barrier polymer via a covalent bond or linking group. Detailed description

[0010] Compounds of the invention provide longer photochromic performance by either reacting with reactive species that may degrade the photochromic dye or by preventing reactive species from approaching the dye or preventing the reactive species from forming.

[0011] Photochromic compounds in the coloured state are particularly susceptible to reactive species such as oxygen and other radicals. This is because the coloured form of the dye has a series of conjugated double bonds. Conjugated double bonds are known to be susceptible to attack by oxygen centred radicals and other radicals. This is illustrated below with both a spirooxazine and chromene; other photochromic compounds are similarly vulnerable when in the coloured state.

double bond

conjugated double bonds

[0012] Although the coloured form is more susceptible to degrading reactions, the clear form may also be degraded itself.

[0013] As a result of the reactive nature of photochromic compounds, they typically have a limited lifespan and this limits their use in many applications. Applications such as architectural glass, printing, security inks, automotive windscreens all require the photochromic moiety to continue to function for a long period (greater than at least 2 years). [0014] Improved fatigue properties may manifest themselves in the observation of longer lived photochromic effect in the application. Performance may also be apparent in observing consistent attainment of maximum and minimum optical density as fatigue may also cause lower maximum optical density and higher residual colour after fading. Frequently, complete degradation of a photochormic system in an application such as optical lenses causes the presence of a residual colouration (brown or grey) with no observable photochromic effect.

[0015] Where used herein the term alk used alone or in words such as alkoxy, alkylthio, alkanoyl and in the term alkyl, unless indicated to the contrary, includes groups Ci to C₂o alkyl, preferably Ci to Cio alkyl and more preferably Ci to C₆ alkyl.

[0016] Where used herein the term substituted alkyl and substituted alkoxy includes alkyl and alkoxy substituted with one or more substitutents selected from the group consisting of halo, hydroxy, alkoxy, haloalkoxy, aryloxy, carbocyclic and heterocyclic.

[0017] Where used herein the term aryl includes monocyclic and dycyclic aromatic and heteroaromatic compounds of from 5 to 10 ring members. Heteroaromatic compounds may include from 1 to 3 heteroatoms selected from oxygen, nitrogen and sulfur. Preferred examples of aryl include phenyl, pyridyl, indolyl, benzopyranyl and the like.

[0018] Where used herein the term halo preferably means chloro or fluoro. The term halo, when used as a prefix such as in haloalkyl, haloalkoxy or haloaryl includes the presence of one or more halogen substituents.

[0019] Where used herein the term substituted aryl includes aryl substituted with one or more substitutents selected from the group consisting of halo, hydroxy, akyl, alkoxy, alkoxycarbonyl, carboxyl and nitrile. [0020] Where used herein the term acyl includes alkanoyl such as Ci to C₂o alkanoyl and aroyl such as benzoyl.

[0021] Where used herein the term substituted acyl includes acyl substituted with one or more substituents selected from the group consisting of halo, hydroxy, alkoxy, alkyl, aryl and substituted alkoxy.

[0022] Where used herein the term comprise and variations of the word, such as "comprising" and "comprises", is not intended to exclude other additives, components, integers or steps.

[0023] Where used herein the term cycloalkyl includes aliphatic groups containing from 1 to 3 rings and a total of from 4 to 20 carbon atoms.

[0024] Where used herein the term substituted cycloalkyl may include one or more substituents selected from the group consisting of halo, hydroxy, alkoxy and aryl.

[0025] Where used herein the term heterocyclic includes aliphatic groups containing from 1 to 20 carbon atoms and from 1 to 3 heteroatoms independently selected from oxygen, nitrogen and sulphur and up to 3 rings.

[0026] Where used herein the term substituted heterocyclic includes heterocyclic groups substituted with one of more substituents selected from the group halo, hydroxy, alkoxy and aryl.

Brief Description of Drawings

[0027] In the drawings:

Figure 1 is a bar chart showing the relative oxygen transmission of a range of gas barrier polymers; Figure 2 is a graph showing the results of fatigue testing products 1A, 1 B and 1 C referred to in the examples at the maximum absorbance of the coloured form (582 nm) in a (standard methacrylate formulation comprising 1 :4 weight ratio of poly(ethylene glycol)(400) dimethacrylate (PEGDMA) and 2,2'-bis((4- methacryloxyethoxy)phenyl)propane (EBPDMA) with 0.4% azobis(isobutyronitrile) (AIBN)) at a concentration of ca. 1.8 x 10-7 mol/g;

Figure 3 is a graph showing the results of fatigue testing products compound 1A and 3 referred to in the examples incorporated into a matrix consisting of 1 :4 weight ratio of poly(ethylene glycol)(400) dimethacrylate (PEGDMA) and ethoxylated bisphenol-A dimethacrylate (average number of EO units = 2.6) with 0.4% azobis(isobutyronitrile) (AIBN)), at a concentration of ca. 1.8 x 10-7 mol/g; and

Figure 4 is a graph showing the results of fatigue testing products 1A, 1 B and 1 C referred to in the examples in thin films of poly(methyl methacrylate).

[0028] Referring to Figure 1 Examples of useful vinyl monomers for providing high oxygen barrier properties include monomers with a chemical formula I

CH₂=CXY I wherein at least one of X and Y is selected from the group consisting of hydroxyl, acetyl, nitrile and chlorine. Specific examples are listed in Tablei . Figure 1 is a graph of the oxygen transmission coefficients of vinyl group polymers.

[0029] Tablei - Types and functional groups of vinyl group polymers

Names X Y

Polyvinylacetic acid H OCOCH₃

Polyvinyl chloride H Cl

Polyacrylonitrile H CN

Polyvinylidene chloride Cl Cl

Ethylene-vinylalcohol copolymer H H or OH

Polyvinyl alcohol H OH [0030] Structure of the vinyl group polymer

H X

I I — <rC-C^hr-

I I H Y

[0031] The oxygen transmission of polymers and copolymers used in preparing polymeric films industry may be used as a general guide to choosing monomers and comonomers for use in polymeric units in compounds of the invention. For example, the oxygen transmission of a variety of polymer resins is shown in Figure 1 wherein the polymers a shown by the abbreviations listed below.

LDPE : low-density polyethylene

PS : polystyrene

PP : polypropylene

PVAc : polyvinyl acetate

PVC : polyvinyl chloride

PVF : polyvinyl fluoride

PVdC : polyvinylidene chloride

PAN : polyacrylonitrile

EVOH: ethylene-vinylalcohol copolymer

PVA : polyvinyl alcohol

[0032] The compounds of the invention comprise a polymer or polymer section which has high gas barrier properties. Preferably the photochromic will comprise at least 5 and preferably at least 10 monomers of a high barrier polymer. The molecular weight of the high barrier polymer chain is preferably at least 200 and more preferably at least 250.

[0033] In a preferred embodiment the gas barrier polymer comprises repeating units selected from the group consisting of acrylonitrile, methacrylonitrile, vinylchloride, vinylidene chloride, vinyl alcohol, vinyl acetate, polyesters and polyamides optionally copolymerized. [0034] The vinyl polymers may be copolymers of gas barrier units and other vinyl monomer units. Examples of other monomer units include acrylate and methacrylate comonomers and other monomers. Examples of comonomers may be selected from the group consisting of methyl methacrylate, ethyl methacrylate, propyl methacrylate (all isomers), butyl methacrylate (all isomers), 2-ethylhexyl methacrylate, isobornyl methacrylate, methacrylic acid, benzyl methacrylate, phenyl methacrylate, alpha- methylstyrene. methyl acrylate, ethyl acrylate, propyl acrylate (all isomers), butyl acrylate (all isomers), 2-ethylhexyl acrylate, isobornyl acrylate, acrylic acid, benzyl acrylate, phenyl acrylate. styrene, functional methacrylates, acrylates and styrenes selected from glycidyl methacrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate (all isomers), hydroxybutyl methacrylate (all isomers), N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl methacrylate, triethyleneglycol methacrylate, itaconic anhydride, itaconic acid, glycidyl acrylate, 2-hydroxyethyl acrylate, hydroxypropyl acrylate (all isomers), hydroxybutyl acrylate (all isomers), N,N-dimethylaminoethyl acrylate, N, N- diethylaminoethyl acrylate, triethyleneglycol acrylate, methacrylamide, N- methylacrylamide, N,N-dimethylacrylamide, N-tert-butylmethacrylamide, N-n- butylmethacrylamide, N-methylolmethacrylamide, N-ethylolmethacrylamide. N-tert- butylacrylamide, N-n-butylacrylamide, N-methylolacrylamide, N-ethylolacrylamide, vinyl benzoic acid (all isomers), diethylaminostyrene (all isomers), alpha-methylvinyl benzoic acid (all isomers), diethylamino alpha-methylstyrene (all isomers), p-vinylbenzene sulfonic acid, p-vinylbenzene sulfonic sodium salt, trimethoxysilylpropyl methacrylate, triethoxysiiyipropyl methacrylate, tributoxysilylpropyl methacrylate, dimethoxymethylsilylpropyl methacrylate, diethoxymethyl-silylpropylmethacrylate, dibutoxymethylsilylpropyl methacrylate, diisopropoxymethylsilylpropyl methacrylate, dimethoxysilylpropyl methacrylate, diethoxysilylpropyl methacrylate, dibutoxysilylpropyl methacrylate, diisopropoxysilylpropyl methacrylate, trimethoxysilylpropyl acrylate, triethoxysiiyipropyl acrylate, tributoxysilylpropyl acrylate, dimethoxymethylsilylpropyl acrylate, diethoxymethylsilylpropyl acrylate, dibutoxymethylsilylpropyl acrylate, diisopropoxymethylsilylpropyl acrylate, dimethoxysilylpropyl acrylate, diethoxysilylpropyl acrylate, dibutoxysilylpropyl acrylate, diisopropoxysilylpropyl acrylate, vinyl acetate, vinyl butyrate, vinyl benzoate, vinyl chloride, vinyl fluoride, vinyl bromide, maleic anhydride, N- phenylmaleimide, N-butylmaleimide, N-vinylpyrrolidone, N-vinylcarbazole, butadiene, isoprene, chloroprene, propylene and mixtures thereof.

[0035] Further examples of polymers which may be used to provide gas barrier properties in the compounds of the invention include polyesters. Such polyester includes polymers prepared by reacting an organic diacid containing at least one active hydrogen group and diglycidyl ether in the presence of an optional catalyst. An example of such polymers is disclosed in United States Patent 6346596. Further examples of suitable polyesters include reaction products of transesterification resistant diols such as neopentyl glycol or bis-(hydroxyl ethyl resourcinol with a suitable diacid. Such polymers are described in International publication WO 02/22705 the contents of which are herein incorporated by reference. A further example of high gas barrier polymers include aromatic polyamide, such as poly(m-xylylene adipamide) or a copolyamide in which a portion of adipamides is replaced with isophthalamide.

[0036] In one embodiment the photochromic polymer further includes a low Tg polymer, preferably having a Tg of less than 25^QC. The low Tg polymer may be part of the same chain as the gas barrier polymer. Alternatively or in addition the low Tg polymer may be present in a different substituent on the the photochromic moiety. In yet another embodiment the low Tg polymer is present in a branch from the gas barrier bolymer or as a branch from a linker group between the a photochromic moiety and gas barrier polymer. The presence of a low Tg polymer, in addition to the gas barrier polymer can significantly increase the fade speed of the photochromic, that is reduce the VA by at least 20% and more preferably at least 50% when compared with the same photochromic without the low Tg polymer in a rigid host such as a high Tg Polymer (Tg over 50^QC and preferably over 75^QC.

[0037] The photochromic polymers preferably exhibit at least 60% of the initial absorbance when subject to continuous irradiation at the maximum absorbance for a period of one hour at a power of 300W in accordance with the fatigue testing regime set out in Example 5. The photochromic will generally be tested in a rigid lens matrix. The concentration of the photochromic in the rigid lens matrix is preferably about 1.8 x 10-7 mol photochromic/gram of rigid matrix.

[0038] In a preferred embodiment the at least one substituent on the photochromic (PC) is selected from the group of formula Na and Hb:

wherein in the formula Na to lib:

U is a covalent linker to the polymeric group (Poly) and is a bond or a chain containing up to four units defined by any one of formulae Nc to Nf

Nd

O

X' is selected from the group consisting of oxygen, sulfur, amino, alkylamino, C₁ to C₄ alkylene, Ci to C₄ alkyleneoxy, Ci to C₄alkyleneoxy(Ci to C₄alkyleneoxy) carbonyl (Ci to C₄ alkylene);

X" is selected from the group consisting of oxygen, sulfur, amino substituted, alkylamino, Ci to C₄ oxyalkylene, Ci to C₄ oxyalkylene(Ci to C₄ oxyalkylene) and (Ci to C₄ alkylene) carbonyl; n is an integer from 1 to 3; p which when there is more than one may be the same or different is 0 or 1 ; q is 0 or 1 ;

B is a further functional group; t is 0, 1 or 2 and preferably the sum n+t is no more than 3; and

Poly is the position of the covalently bonded gas barrier polymer.

[0039] The purpose of the linking group is to join the one or more polymeric substituents to the photochromic moiety. A linking group may be needed when the polymeric substituent has a functional group that cannot be used directly to join to the dye.

[0040] The group B is an optional but particularly preferred further functional group and t is 0, 1 or 2. [0041] The appropriate linker can be chosen without undue experimentation having regard to the functional substituents in the photochromic moiety. Where the substituent for attachment is nucleophilic the group may be attached via a linker comprising a carbonyl group such as an acid chloride anhydride or the like, whereas in cases where the substituent is electrophilic such as an acid chloride, acid ester or anhydride reaction with a nucleophilic linker or polymer group may be used.

[0042] The substituent B in a particularly preferred embodiment comprised a low Tg polymer group such as described in WO 2004/041961 , WO 2005/105874, WO 2005/105875 or WO2006/024099 and the group B comprises a stabilizing group and t is at least 1. Thus B may comprise a polymer having a Tg of less the 25^QC.

[0043] In another embodiment B comprises a functional group which is reactive with the host matrix so that the photochromic polymer reacts with and becomes tethered to the host matrix such as a monomer composition for forming an optical article.

[0044] In a preferred embodiment of the invention the compound comprises a further polymeric group which may be part of the same chain as a barrier polymer substituent or may be a distinct substituent on the photochromic moiety by virtue of a branched linker. The polymeric substituent may be selected from the group consisting of polyether oligomers, polysubstituted alkylene) oligomers, polyfluoroalkylether oligomers, polydi(Ci to Cio hydrocarbyl)siloxane oligomers, polysilicic acid oligomers (silicates) or derivatives thereof, poly (ZSi(OH)₃) oligomers and derivatives thereof, poly (ZSiCI₃) oligomers and derivatives thereof, poly (ZSi(OMe)₃) oligomers and derivatives thereof, and mixtures thereof wherein Z is an organic group. Preferably Z is selected from the group consisting of hydrogen, alkyl, optionally substituted alkyl, haloalkyl, cycloalkyl, optionally substituted cycloalkyl, hydroxyl, amino, optionally substituted amino, alkoxy, aryloxy, aryl, optionally substituted aryl, carboxylic acid and derivatives thereof. A particularly preferred subset of these later oligomers are colloquially known as Polyhedral Oligomeric Silsesquioxanes (POSS). Compounds that contain a photochromic moiety and a POSS oligomer can display crystalline state photochromism. [0045] The more preferred low Tg polymers are polydi(Ci to Cio hydrocarbyl)siloxane oligomers particularly polydialkylsiloxanes such as polydimethylsiloxane and polyether oligomers particularly polyalkyleneoxy oligomers such as polyethyleneglycol. The moleculer weight of the low Tg segment is preferably at least 250.

[0046] Examples of suitable polymeric groups include groups of formula Ilia:

-(X)p(R)_q - R^' lll(a) wherein:

X is selected from oxygen, sulfur, amino such as Ci and C₆ alkyl amino, Ci to C₄ alkylene (preferably methylene); p is 0 or 1 ; q is the number of the monomer units R¹ in said oligomer and is preferably at least 5;

R, which may be the same or different, are selected from the group consisting of:

C₂ to C₄ alkylene such as ethylene, propylene and butylene; chloro(C₂ to C₄ alkylene) such as vinylchlohde, vinylidenedichloride and chloropropene; vinyl acetate (optionall hydrolyzed);vinyl alcohol; ethylene-vinyl alcohol copolymer; acrylonitrile; copolymers of two or more thereof and copolymers of at least one thereof with a comonomer such as acrylate and/or methacrylate comonomers;

R is selected from hydrogen, C₁ to C₆ alkyl and C₁ to C₆ haloalkyl, hydroxyl, optionally substituted amino, optionally substituted aryl carboxylic acid and derivatives thereof and preferably R is selected from the group consisting of hydrogen, C₁ to C₆ alkyl, unsaturated C₂ to C₂₀aliphatic, substituted amino, optionally substituted aryl and alkyl and aryl esters of carboxyl.

[0047] In one embodiment of the invention an additional polymeric group is present which is a poly(substituted alkylene) polymer comprising a plurality of monomer units of formula NIb: R¹

CH -C -

R 2' R' 1Mb wherein

R¹, which is independently selected for each of said plurality of monomer units, is selected from the group consisting of hydrogen, fluoro, alkyl, hydroxy alkyl, and alkoxy;

R² in each of said monomer units is independently selected from the group consisting of, alkoxy, aryl, aryloxy, heterocyclic arylalkyl, alkylaryl, carboxyl, and the group of formula:

O

C XR⁸ wherein R⁸ is selected from the group consisting of alkyl, substituted alkyl, carbocyclic, substituted carbocyclic, heterocyclic, substituted heterocyclic; and X is selected from the group consisting of a bond, oxygen, sulphur and the group NR⁷' wherein R⁷ is selected from the group consisting of hydrogen, alkyl, substituted alkyl, aryl and substituted aryl, carbocyclic, substituted carbocyclic, heterocyclic and substituted heterocyclic; wherein preferably at least one of R⁷' and R⁸ is other than hydrogen and the group of formula:

-L-(O)_q-(Z-O)_p-ZY'; and O

C _ Cr(Q_q(ZQ_pZY¹ wherein p is from 1 to 20, q is 0 or 1 , Z is selected from the group consisting of C₂ - C₄ alkylene, dialkylsilyl, diarylsilyl and diaryloxysilyl; L is a bond or a linking group such as Ci to C₆ alkylene, aryl, alkaryl and aralkyl; and Y is a terminal group selected from the group consisting of hydrogen, alkyl, hydroxyl and alkoxy, alkoxyalkoxy, hydroxyalkoxy and aryloxy, W-(C₁ to C₆ alkyl)silane, CIi(C₁ to C₆ alkyl)phenyl silane;

R² , which is independently selected for each of said plurality of monomer units, is hydrogen and R² and R² may together form a group of formula O O

C — X — C wherein

X is selected from the group consisting of oxygen, surfur and the group NR⁷ wherein R⁷ is selected from the group of hydrogen, alkyl, aryl, substituted alkyl and substituted aryl.

[0048] The polymer comprising the monomeric unit of formula I may be a homopolymer or copolymer. It may be a copolymer of two or more units of formula I or a copolymer of at least one unit of formula I and one or more comonomer units derived from unsaturated compounds. Where the polymer is a copolymer suitable comonomer units may include one or more distinct units of formula III or comonomers of formula IV:

R³ R⁵

C C IV

R⁴ R⁶ wherein

R³, R⁴, R⁵ and R⁶ are independently selected from the group consisting of hydrogen, halogen, alkyl, substituted alkyl, aryl, substituted aryl and haloalkyl. The copolymer may be a random or block copolymer.

[0049] Examples of the group R include polymers of formula IVb

wherein t is from 2 to 500, preferably 2 to 200, more preferably 2 to 100 and most preferably from 5 to 50 and w is from 0 to 500, preferably 0 to 100 and more preferably 0 to 50. [0050] Wherein when the polymer is a copolymer the distinct units may be present as blocks or randomly distributed.

[0051] The invention further provides a photochromic comprising at least one polymeric substituent formed by a chain growth polymerization method. A particularly preferred method of chain growth is by living polymerisation, particularly living free radical polymerization.

[0052] The compounds of the invention may be incorporated in polymerizable compositions used to form the host matrix so that they become bound within the polymerized host. In one embodiment of the invention the photochromic compound of the invention comprises a terminal group (the group B in the compound of formula lib or the group Y' in the compound of the invention of formula iiib) which is reactive with the polymerizable composition during curing. For example, the polymerizable group may be an unsaturated group which becomes tethered to the host polymer during curing of the host composition. The group may be an alcohol, acid, amine or other group for reacting with co-reactive functional groups in a host monomer. In this embodiment the compound of the invention becomes chemically bound with the polymeric substituent forming a tether bound (particularly by covalent bonds) to the host.

[0053] In an embodiment the invention provides a composition for forming a photochromic light transmissible article the composition comprising: a polymerizable composition comprising a monomer component including a crosslinking monomer; and a photochromic polymer reactive with the monomer component during curing.

[0054] The polymerizable composition may comprise one or more of monomers, prepolymers, crosslinking monomers and binders. [0055] In one embodiment a photochromic polymer thus comprises a photochromic moiety and at least one pendant group comprising a functional group reactive with a monomer composition for forming a photochromic polymeric article.

[0056] The photochromic monomer may be incorporated into an existing polymer, for example, by reactive processing of the polymer during extrusion or other processing step. Examples of reactive processing include grafting and transesterification.

[0057] Examples of preferred polymerizable reactive groups may be selected from the group consisting of amino; alkylamino (including mono and di-alkylamino); hydroxyl; thio; mercapto; epoxy; carbamate; alkylhalo; unsaturated groups (such as acryloyl, methacryloyl, acryloyloxy and methacryloyloxy), maleimides; the group of formula - SiX¹X²X³ wherein X¹, X² and X³ are independently selected from the group consisting of hydrogen, halogen, hydrocarbyl and hydrocarbyloxy and wherein at least one of X¹, X² and X³ is selected from hydrogen, halogen and hydrocarbyloxy; dithioester (-S-C=S-R); trithiocarbonate (-S-C=S-S-R); dithiocarbamate (-S-C=S-NRR); xanthate (-S-C=S-O-R); carboxylic acids; carboxylic esters; and Ci to C₆ alkyl substituted with a group selected from hydroxy, thio, amino, alkyl amino, carboxyl, (C₁ to C₆ alkoxy)carboxyl, acryloyl, methacryloyl, acryloyloxy and methacryloyloxy.

[0058] In one embodiment the reactive group is a radical capping group adapted to be reversibly cleaved from the compound under activating conditions to provide a reactive radical. Such radical groups will be known to those skilled in the art for use in living free radical polymerisation and include groups such as dithioester (-S-C=S-R); trithiocarbonate (-S-C=S-S-R); dithiocarbamate (-S-C=S-NRR); xanthate (-S-C=S-O-R); carboxylic acids; carboxylic esters and nitroxide.

[0059] Preferably halogen is chloro; preferred hydrocarbyl is Ci to C₆ alkyl and phenyl; preferred hydrocarbyloxy is C₁ to C₆ alkoxy. [0060] The reactive group may be an unsaturated group. Most preferably the unsaturated group is selected from the group consisting of (meth)acryloyl, (meth)acryloyloxy, allyl, allyloxy, maleimides, styryl and norbornenyl. The reactive group may also be of formula SiX¹X²X³ wherein X¹ , X² and X³ are independently selected from the group consisting of hydrogen, C₁ to C₄ alkyl, halogen and C₁ to C₄ alkoxy and at least one of X¹ , X² and X³ is selected from hydrogen, halogen and C₁ to C₄ alkoxy.

[0061] Particularly preferred examples of the group B in formula Na and Nb are of formula Ng to III.

O

(x% _poαc=cι-b iig

(X)_{p p}-CH=α-b Mh

(X)p(X')_q (YH)_W Mk

(X)_p(X')_q (NRR")_w wherein: X' as defined for formula Na and lib;

X" is as defined for formula Na and lib; preferably selected from the group consisting of Ci to C₄ alkylene; where Y is oxygen or sulphur; w is the number of hydroxyl or thiol groups at the terminal end of the reactive group; p is selected from 0 and 1 ; q is selected from 0 and 1 ;

J is hydrogen or C₁ to C₄ alkyl (preferably hydrogen or methyl);

R is an oligomer as defined;

R' is hydrogen, C₁ to C₆ alkyl or substituted (C₁ to C₆) alkyl; and

R" is hydrogen (C₁ to C₆) alkyl or substituted C₁ to C₆) alkyl.

[0062] In a further aspect the invention provides a photochromic composition comprising a polymeric substrate and photochromic compound comprising a photochromic moiety and at least one polymeric substituent comprising a carbon backbone and pendant functional groups. The polymeric substrate may be in the form of a coating composition, a polymerizable composition or rigid polymer such as rigid polymers used in optical applications.

[0063] The polymeric photochromic may be prepared in a number of ways such as: i). Growth of the polymeric substituent from a photochromic dye having a suitable initiation group; ii). Growth of the polymer from a precursor to the photochromic dye and subsequent formation of the photochromic moiety from the precursor group; iii). Preparation of the polymeric portion comprising the gas barrier polymer and subsequent joining of the photochromic moiety be any suitable organic synthesis procedure ; and iv). Copolymerization of a monomer comprising the photochromic moiety with monomers for providing gas barrier properties such as the vinyl gas barrier monomers referred to above.

[0064] Polymerisation of the gas barrier polymer may be carried out by radical polymerization, ionic polymerization (anionic or cationic) or by group transfer polymerization.

[0065] In a preferred embodiment the polymerization is by radical polymerization such as living or other radical polymerization and in a particularly preferred embodiment the polymerization is conducted by living free radical polymerization (also referred to as step growth radical polymerization. Specific examples of living free radical polymerization include RAFT, ATRP or lniferter mediated living free radical polymerization. Each of these methods is known in the art and described in our copending International Publication WO2005/105875. RAFT mediated living free radical polymerization is particularly preferred. RAFT polymerization of one or more vinylic monomers is described for example, in detail in WO-A-98/01478.

[0066] A RAFT polymerization system is basically a free-radical polymerization system which additionally comprises a specific chain transfer agent, the "RAFT agent", usually a thiocarbonyl-thio compound, as described more particularly in WO-A-98/01478. The RAFT agent is preferably a compound of the following formula:

S Il z-C-S-R wherein

Z is selected from hydrogen, fluorine, chlorine, optionally substituted alkyl, optionally substituted aryl. optionally substituted heterocyclyl, optionally substituted alkylthio, -COOR", -COOH, -O₂CR", -CONR"₂), -CN, -P(=0)OR"₂, and -P(=0)R"₂]-, wherein R" is selected from optionally substituted CrCi₈ alkyl, C₂-Ci₈ alkenyl, aryl, heterocyclyl, aralkyl, alkaryl wherein the substituents are independently selected from the group that consists of epoxy, hydroxy, alkoxy, acyl, acyloxy. carboxy (and salts), sulfonic acid (and salts), alkoxy- or aryloxy-carbonyl, isocyanato, cyano, silyl. halo, and dialkylamino; and

R is selected from optionally substituted alkyl; an optionally substituted saturated, unsaturated or aromatic carbocyclic or heterocyclic ring; optionally substituted alkylthio; optionally substituted alkoxy; optionally substituted dialkylamino.

[0067] Preferred thiocarbonylthio compounds useful for the purposes of the present invention include, for example, dithiobenzoic acid benzyl ester; dithiobenzoic acid 1 - phenyl-ethyl ester; dithiobenzoic acid 1 -methyl-1 -phenyl-ethyl ester; acetic acid 1 - thiobenzoylsulfanyl-ethyl ester; dithiobenzoic acid 1-(4-methoxyphenyl)-ethyl ester; thiobenzoylsulfanyl-acetic acid ethyl ester; 2-methyl-2- thiobenzoylsulfanyl-propionic acid ethyl ester; dithiobenzoic acid tert. -butyl ester; dithiobenzoic acid cyano-dimethyl-methyl ester (=2-(2-cyanopropyl) dithiobenzoate); dithiobenzoic acid 1 ,1 ,3,3-tetramethyl-butyl ester; dithiobenzoic acid 1-(4-chloro-phenyl)-1 -methyl-ethyl ester; 4-chloro-dithiobenzoic acid 1 -methyl-1 -phenyl-ethyl ester; naphthalen-1 -carbodithionic acid 1 -methyl-1 -phenyl- ethyl ester and 4-cyano-4-methyl-4-thiobenzoylsulfanyl-butyric acid. 2-(2-cyanopropyl) dithiobenzoate) is mostly preferred.

[0068] When the photochromic polymer is formed by copolymerization of a photochromic monomer with a gas barrier and optionally further unsaturated monomers the photochromic monomer may be of formula:

CH₂=CR'"-L-(O)_q-(Z-O)p-Z(PC); and O

Ch^CR C _ OLXQq(ZO)PZ(PC)¹

wherein

R'" is hydrogen or methyl; p is from 1 to 20, q is 0 or 1 ; Z is selected from the group consisting of C₂ - C₄ alkylene, dialkylsilyl, diarylsilyl and diaryloxysilyl;

L is a bond or a linking group such as Ci to C₆ alkylene, aryl, alkaryl and aralkyl; and

(PC) is a photochromic moiety.

[0069] The invention further provides a living free radical process for preparing a photochromic polymer providing gas barrier stabilisation of the photochromic the method comprising living free radical polymerisation of free-radically polymerizable monomers comprising vinylic monomers for forming a gas barrier polymer, said process comprising forming a mixture of:

(a) One or more vinyl monomers of chemical formula CH₂=CXY wherein at least one of X and Y is selected from the group consisting of hydroxyl, acetyl, nitrile and chlorine and the other is selected from the group consisting of hydrogen and chlorine and copolymers of said monomer;

(b) Optionally a further vinyl monomer such as an acrylate and/or methacrylate monomer;

(c) a living free radical chain transfer agent such as a RAFT, ATRP or lniferter living free radical mediation agent; and

(d) a photochromic reagent comprising a living free radical initiation group or radically polymerisable vinyl group; and reacting the mixture at a temperature of more than 50^QC and preferably more than 60^QC.

[0070] The compound of the invention comprises a photochromic moiety. Preferred examples of photochromic moieties include the spirooxazine of formula V, chromene of formula XX, fulgide/fulgamide of formula XXX or an azo dye of formula XL. Formulae V, XX, XXX and XL are described below with reference to examples.

[0071] Preferred spirooxazines of the general formula III can be suitably used.

[0072] In the general formula V, R³, R⁴ and R⁵ may be the same or different and are each an alkyl group, a cycloalkyl group, a cycloarylalkyl group, an alkoxy group, an alklyleneoxyalkyl group, an alkoxycarbonyl group, a cyano, an alkoxycarbonyl alkyl group, an aryl group, an arylalkyl group, an aryloxy group, an alkylenethioalkyl group, an acyl group, an acyloxy group or an amino group, R⁴ and R⁵ may together form a ring, and R³, R⁴ and R⁵ may optionally each have a substituent(s). The substituent(s) can includes (include), besides the above-mentioned groups, halogen atom, nitro group, heterocyclic group, etc.

[0073] The group represented by moiety Va:

is a substituted or unsubstituted bivalent aromatic hydrocarbon group or a substituted or unsubstituted bivalent unsaturated heterocyclic group. The group represented by moiety Vb:

is a substituted or unsubstituted bivalent aromatic hydrocarbon group or a substituted or unsubstituted bivalent unsaturated heterocyclic group. Specific examples of the bivalent aromatic hydrocarbon group are groups of 6 to 14 carbon atoms derived from benzene ring, naphthalene ring, phenanthrene ring, anthracene ring or the like. Specific examples of the bivalent unsaturated heterocyclic group are groups of 4 to 9 carbon atoms derived from furan ring, benzofuran ring, pyridine ring, quinoline ring, isoquinoline ring, pyrrole ring, thiophene ring, benzothiophene ring or the like. [0074] The substituents can be the same groups as mentioned above with respect to R³, R⁴ and R⁵. In particular, a group represented by:

-NR⁶R⁷

(wherein R⁶ and R⁷ are each an alkyl group, an alkoxy group, an allyl group or the like, each of which may be substituted; and R⁶ and R⁷ may be bonded and cyclized with each other to form a nitrogen-containing heterocyclic ring) is preferable from the standpoint of high density of its developed colour in the initial photochromic performance.

[0075] In a particularly preferred embodiment the photochromic compounds of the invention are of formula Vl

wherein R³, R⁴, R⁵, R⁸ R⁹, R¹⁰ and R¹¹ are independently selected from the group consisting of hydrogen, alkyl, halo, haloalkyl, cycloalkyl, cycloarylalkyl, hydroxy, alkoxy, alkyleneoxyalkyl, alkoxycarbonyl, aryl, arylalkyl, aryloxy, alkylenethioalkyl, acyl, acyloxy, amino, NR⁶R⁷, cyano and the group L(R)_n wherein at least one of R³, R⁸ and R⁹ is the polymeric substituent group of formula L(R)_n wherein L, R and n are hereinbefore defined and wherein there is more than one L(R)_n group in the groups R⁸, R³, R⁴ and R⁵ and one or more R groups may optionally be linked together to form one or more bridging polymeric substituent. The m is an integer and may be 0, 1 or 2 wherein m is 2 the groups may be independently selected.

[0076] In the compound of formula Vl the total of the number of monomer units in polymeric substituents, (R)_n, is at least 7 and preferably at least 12. [0077] More preferably, the substituent R³ is selected from the group consisting of alkyl, cycloalkyl, cycloarylalkyl, alkyleneoxyalkyl, aryl, arylalkyl alkylenethioalkyl, and the group L(R)_n and more preferably R³ is selected from alkyl, cycloalkyl, cycloarylalkyl, alkenyloxyalkyl, aryl, arylalkyl, and the group L(R)_n and preferably R⁴ and R⁵ are indefinitely selected from alkyl, cycloalkyl and aryl.

[0078] R⁸ and R⁹ are independently selected from hydrogen and L(R)_n; R¹⁰ and R¹¹ are independently selected from the group consisting alkyl, cycloalkyl, cycloarylalkyl, alkoxy, -NR⁶R⁷, cyano, alkyleneoxyalkyl, alkoxycarbonyl, aryl, arylalkyl, aryloxy, alkylenethioalkyl, aryl aryloxy and amino and most preferably R¹⁰ and R¹¹ are independently selected from alkyl, cycloalkyl, alkoxy, NR⁶R⁷ and cyano; and m is 0 or 1.

[0079] Examples of the preferred fused aromatic ring groups of formula Va include Va(i);

wherein R⁹ and R¹¹ are as hereinbefore defined.

[0080] Examples of the preferred fused aromatic ring group of formula NIb include Vb(i), Vb(ii), Vb(iii) and Vb(iv).

[0081] Specific examples of the group of formula Va(i) include:

[0082] Specific examples of the group of formula 1Mb include:

[0083] One particularly preferred embodiment of the compounds of formula Vi has the formula Via:

[0084] The more preferred compounds of formula Via are compounds wherein R⁴ and R⁵ are preferably independently selected from the group consisting of Ci to C₄ alkyl and the group wherein R⁴ and R⁵ link together to form a cycloalkyl of from 4 to 6 carbon atoms.

[0085] R⁸ and R⁹ are independently selected from the group consisting of hydrogen, halogen, cycloalkyl, cycloaryl alkyl, hydroxy alkoxy, cyano, alkenyloxyalkyl, alkoxycarbenyl, aryl, aralkyl, aryloxy, alkylene, thioalkyl and the polymeric substituent of formula L(R)_n wherein L, R and n are as hereinbefore defined;

[0086] R¹⁰ and R¹¹ are independently selected from the group consisting of hydrogen, halogen, cycloalkyl, cycloaryl alkyl, alkoxy, cyano, alkenyloxyalkyl, alkoxycarbonyl, aryl, arylalkyl, acyloxy and alkylenethioalkyl. Most preferably R¹⁰ and R¹¹ are hydrogen; and at least one of R⁸ and R⁹ is the group L(R)_n wherein the total number of monomer units in R is at least 10 and more preferably at least 12.

[0087] In order to provide an increase in fade rate of the photochromic in a polymer (preferably a polymer of high Tg) article, the size of the polymer chain must be greater than a certain size. The minimum size will depend on the nature of the polymeric substituent chain and the linking group. It is believed that the fade is significantly accelerated where a polymer chain may adopt a conformation in which a portion of the chain is adjacent the oxazine ring.

[0088] The more preferred compounds of the invention are of formula (VIb)

where the substituents are hereinbefore described and even more preferably R³ is Ci to C₄ alkyl; C₃ to C₆ cycloalkyl, aryl, alkylaryl, arylalkyl and L(R)_n; R^5a and R^5b are independently selected from Ci to C₆ alkyl C₃ to C₆ cycloalkyl, aryl; R⁸ and R⁹ are selected from hydrogen, hydroxy, Ci to C₆ alkoxy; R¹⁰ is selected from the group hydrogen, hydroxy, Ci to C₆ alkoxy -NR⁶R⁷ wherein R⁶ and R⁷ are independently hydrogen, C₁ to C₆ alkyl and wherein R⁶ and R⁷ may together form a divisional hydrocarbon chain of 4 to 6 carbon atoms.

[0089] As we have discussed above, in order to maximise the rate of colouration and fade in polar and non-polar polymers it is preferred that one of R³, R⁸ and R⁹ is L(R)_n comprising at least 10, more preferably at least 12 monomer units and the other two of R³, R⁸ and R⁹ are other than L(R)_n where L(R)_n contains 7 monomer units.

[0090] In compounds where more than one of R³, R⁸ and R⁹ is L(R)_n comprising at least 7 monomer units, the effect on the rate of colouration and fade will depend to some extent on the polymeric substituent and type of polymer. In cases where the polymer and polymeric substituents are compatible, the rate of fade may be decreased and when the polymeric substituent and resin are less compatible, the effect may be less or fade may be increased.

[0091] We have found that for compounds of formula Vl a (preferably VIb) if R⁸ and R⁹ are shorter chains or smaller substituents they are also useful in controlling the rate of fade though to a more limited extent.

[0092] In a further embodiment, the invention therefore provides compounds of formula Via (preferably VIb) wherein R⁸ and R⁹ are each selected from groups of formula I and groups of formula L(R)_n as hereinbefore defined and the group LR¹¹ wherein R¹¹ is lower alkyl, lower haloalkyl, lower polyalkyleneoxy aryl and aryl(lower alkyl). The term lower is used to mean up to 6 carbon atoms in the chain and preferably up to 4.

[0093] In yet another embodiment we provide an intermediate for preparation of compounds of the invention, the intermediate being of formula IVa and more preferably VIb wherein R⁸ and R⁹ are selected from XH wherein X is hereinbefore defined. Preferably R⁸ and R⁹ are the same.

[0094] Compounds of the invention may be prepared by reaction of intermediates Vila or VIIb and VIII.

Vila VIIb

VIII

[0095] One method for preparing compounds of the invention comprises reacting a methylene indolene of formula Vila or Fishers base or indolium salt of formula VIIb where J is halogen, particularly the iodide salt, wherein R¹³ is R⁹ and R¹⁴ is R³ with a nitrosohydroxy compound of formula VIII to provide a compound of the invention of formula Vl.

[0096] Alternatively, a methylene indolene of formula Vila or indolium salt of formula VIIb may be reacted with a nitrosohydroxy compound of formula VIII wherein R¹² and R¹³ are independently selected from the group consisting of hydrogen and -XH and at least one of R¹² and R¹³ is -XH to provide an intermediate of formula IX.

and reacting the compound of formula VIII with a compound of formula IX JL(R)_n X wherein J is a leaving group to form a compound of formula Vl wherein at least one of R⁸ and R⁹ are the group L(R)_n.

[0097] Alternatively or in addition the compound of formula IV wherein R³ is L(R)_n may be prepared by reacting the compound of formula Vila or VIIb with a compound of formula X to provide a compound of formula Vila and VIIb where R¹⁴ is L(R)_n and reacting the compound of formula Via or VIb with a compound of formula VIII to provide a compound of formula IV wherein R³ is L(R)_n.

[0098] Specific examples of compounds of formula X, include J L(R)_n where J is chlorine, L a linker is of formula Na to lib where p is O and R is any one of the the barrier polymer.

[0099] Compounds of formula Xl

Xl having a wide variety of the fused aromatic groups B may be prepared using the intermediate of formula VIIc.

[0100] The fused aromatic group B and its substituents may be chosen to provide the desired colour of the photochromic compound. Such compounds provide a versatile method of preparation of rapid fade spiroindolineoxazines.

[0101] Examples of suitable substituted methylene indolene compounds of formula Va and Vb include 5-amino indolene compounds described by Gale & Wiltshire (J. Soc. Dye and Colourants 1974, 90, 97-100), 5-amino methylene compounds described by Gale, Lin and Wilshire (Aust. J. Chem. 1977 30 689-94) and 5-hydroxy compounds described in Tetrahedron Lett. 1973 12 903-6 and in US Patent 4,062,865.

[0102] One of the preferred groups of photochromies are the spiropyrans. Examples of spiropyrans include compounds of formula XIX and XX

wherein in XIX the groups X, Y, Z and Q may be substituents including where one or more thereof form a carbocyclic ring optionally fused with aryl and the substituents R²³ and R²⁴ may be present in any ring; and wherein

B and B are optionally substituted aryl and heteroaryl; and

R²², R²³ and R²⁴ are independently selected from hydrogen; halogen; C₁ to C₃ alkyl; the group L(R)_n; and the group of formula COW wherein W is OR²⁵, NR²⁶R²⁷, piperidino or morpholino wherein R²⁵ is selected from the group consisting of Ci to C₆ alkyl, phenyl, (Ci to C₆ alkyl)phenyl, Ci to C₆ alkoxyphenyl, phenyl Ci to C₆ alkyl, (Ci to C₆ alkoxy)phenyl, Ci to C₆ alkoxy C₂ to C₄ alkyl and the group L(R)_n; R²⁶ and R²⁷ are each selected from the group consisting of Ci to C₆ alkyl, C₅ to C₇ cycloalkyl, phenyl, phenyl substituted with one or two groups selected from C₁ to C₆ alkyl and C₁ to C₆ alkoxy and the group L(R)_n; R²² and R²³ may optionally form a carboxylic ring of 5 or 6 ring members optionally fused with an optionally substituted benzene and wherein at least one of the substituents selected from the group of substituents consisting of B and B^', R²², R²³, R²⁴, R²⁵, R²⁶ and R²⁷ is the group L(R)_n.

[0103] When R²² and R²³ are carbocyclic a preferred compound is of formula XX(d)

where R²², R²⁸ an

.

[0104] Preferably B and B' are independently selected from the group consisting of aryl optionally substituted with from 1 to 3 substituents, heteroaryl optionally substituted with from 1 to 3 substituents. The substituents where present are preferably selected from the group consisting of hydroxy, aryl, C₁ to C₆) alkoxyaryl, (C₁ to C₆) alkylaryl, chloroaryl (C₃ to C₇) cycloalkylaryl, (C₃ to C₇) cycloalkyl, (C₃ to C₇) cycloalkoxy, (C₁ to C₆) alkyl, aryl (C₁ to C₆) alkyl, aryl (C₁ to C₆) alkoxy, aryloxy, aryloxyalkyl, aryloxy (C₁ to C₆) alkoxy, (C₁ to (C₆) alkylaryl, (C₁ to C₆) alkyl, (C₁ to C₆) alkoxy, amino, N-(C₁ to C₆) alkyl amino, ipirazino, N-aryl piperazino, indolino, piperidino, aryl pipersillins, morpholino, thiomorpholino, tetrahydro quinolino. [0105] NR²⁹R³⁰ wherein R²⁹ and R³⁰ are independently selected from the group selected from Ci to C₆ alkyl, phenyl, C₅ to C₇ cycloalkyl and the group wherein R²⁹ and R³⁰ form a linking group of 4 or 5 linking groups comprising methylene groups and optionally containing one or two hetero atoms and optionally further substituted by C₁ to C₃ alkyl and the group L(R)_n.

R²² is selected from the group consisting of hydrogen, C₁ to C₆ alkyl; COW where

W is OR²⁵ wherein R²⁵ C₁ to C₆ alkyl; and the group NR²⁶R²⁷; wherein R²⁶ and R²⁷ are independently C₁ to C₆ alkyl; and the group L(R)_n. [0106] Particularly referred naphthopyran compounds are of formula XX(a):

[0107] Or the corresponding compound in which the oxygen of the pyran ring is attached to the 2-position of the naphthylene group, i.e. the core of the photochromic is of formula

to

than the 1 position wherein

R²⁰ and R²¹ are independently selected from the group consisting of hydrogen, hydroxy, alkoxy, amino, alkylamino, dialkylamino and L(R)_n;

R²² is the group COW where W is C₁ to C₆ alkoxy or the group L(R)_n; R²³ is selected from the group consisting of hydrogen and NR²⁶R²⁷ where R²⁶ are independently selected from the group consisting of Ci to C₆ alkyl and where R²⁶ and R²⁷ may together form an alkylene group of 4 to 6 carbon atoms;

R²⁴ is hydrogen or the group L(R)_n; and wherein at least one of R²² and R²⁴ is L(R)_n-

[0108] Compounds of formula XX wherein R²³ and/or R²⁴ comprise the polymeric substituent group L(R)_n may be prepared from a suitably substituted acetophenone, benzophenone or benzaldehyde of formula XXI(a). In this process the compound of formula XXI (a) (or a polyhydroxy compound where more than one substituent is required) is reacted with an polymeric substituent esterified toluene sulfonate of formula XXI to provide the corresponding polymeric substituent ether of formula XXI(b). The aromatic polymeric substituent ether of formula XXI (b) is reacted with an ester of succinic acid such as the dialkyl succinate of formula XXI(c). A Stobbe reaction produces the condensed half ester of formula XXII which undergoes cyclo dehydration in the presence of acidic anhydride to form the naphthalene polymeric substituent ether of formula XXIII. This compound of formula XXIII may be reacted with acid such as hydrochloride acid and an anhydrous alcohol such as methanol to form the corresponding naphthol shown in formula XXIV which is in turn coupled with the propargyl alcohol of formula XXV to form the polymeric substituent substituted naphthopyran of the invention of formula XX(b).

XXI XX I (a)

XXIII XXIV

XX(b)

[0109] Alternatively, compounds of formula XX(c) in which at least one of the geminal phenyl groups is substituted by a polymeric substituent may be prepared from the benzophenone of formula XXI(f). In this process the benzophenone substituted with the appropriate hydroxyl groups is reacted with the polymeric substituent ester of toluene sulfonate of formula XXI(e) to form the corresponding polymeric substituent substituted benzophenone of formula XXI(g). The corresponding propargyl alcohol of formula XXV(a) is prepared from the benzophenone by reaction with sodium acetylide in a solvent such as THF. This propargyl alcohol of formula XXV(a) is coupled with the appropriate substituted naphthol of formula XXIV(b) to form the polymeric substituent substituted naphthopyran of formula XX(c).

XX(C)

[0110] A further option for forming polymeric substituent substituted pyrans of the invention of formula XX(d) in which the polymeric substituent is present in the 5-position of the naphthopyran may utilise the corresponding carboxylated naphthol of formula XXIII(a). In such a process the naphthol of formula XXIII(a) is reacted with an appropriate polymeric substituent of formula XXI(d) (particularly where linking group L comprising oxygen) to provide a polymeric substituent ester of formula XXI V(a). The polymeric substituent naphthol ester of formula XXIV(a) may be reacted with propargyl alcohol of formula XXV to provide the naphthol of formula XX(d) in which the polymeric substituent is present in the five position.

B^' L(R)n

[0111] In a further alternative compounds of formula XX wherein R²² comprises the polymeric substituent L(R)_n may be formed by reacting a compound of formula XX(e) with an acid chloride or anhydride substituted polymeric substituent to provide a compound of formula:

[0112] Examples of fulgides and fulgimides include compounds of formula XXX and more preferably XXXa:

wherein

Q is selected from the group consisting of optionally substituted aromatic, optionally substituted heteroaromatic (where said aromatic/heteroaromatic may be mono or polycyclic aromatic/heteroaromatic);

R³⁰, R³² and R³³ are independently selected from the group consisting of a Ci to C₄ alkyl, Ci to C₄ alkoxy phenyl, phenoxy mono- and di(Ci-C₄) alkyl substituted phenyl or phen(Ci-C₄)alkyl and R³² and R³² optionally together form a fused benzene which may be further substituted;

A is selected from the group consisting of oxygen or =N-R³⁶, in which R³⁶ is C₁-C₄ alkyl or phenyl,

B is selected from the group consisting of oxygen or sulfur;

R³⁴ and R³⁵ independently represents a CrC₄ alkyl, phenyl or phen(Ci-C₄) alkyl or one of R³⁴ and R³⁵ is hydrogen and the other is one of the aforementioned groups, or R³⁴R³⁵ represents an adamantylidine group; and wherein at least one of R³⁰, R³¹, R³², R³⁵ and R³⁶ is the group L(R)_n.

[0113] The fulgides and fulgimides comprising polymeric substituent substituents in accordance with the invention may be particularly useful in molecular switches.

[0114] The fulgides and fulgimides of formula XXX may be formed in accordance with procedures similar to those described in US Patent 4,220,708. Fulgides of formula XXX(a) in which the group A- is oxygen may be prepared from five membered heterocycle of formula XXX by reaction with an ester of succinic acid of formula XXXII wherein R³⁷ is a residue of an alcohol, by a Stobbe condensation reaction. Hydrolysing the half ester product of XXXIII formed in the reaction provides the diacid of XXXIII wherein R³⁷ is hydrogen. Heating of the diacid of formula XXXIII yields the succinic anhydride product of formula XXXIII(a). The Stobbe condensation may be carried out by refluxing in t-butanol containing potassium t-butoxide or with sodium hydride in anhydrous toluene. Compounds of the invention of formula XXX(b) in which A- of formula XXX is N-36 may be prepared from the compound of XXX(a) by heating the anhydride and a primary amine R³⁶NH₂ to produce the corresponding half amide which can in turn be cyclised to form the imide of formula XXX(b) for example by heating with an acid chloride or acid anhydride. Alternatively the half ester Stobbe condensation product of formula XXX can be converted to the imide of XXX(b) by reaction with a compound of formula R³⁶NHMgBr to produce the corresponding succinamic acid which may be dehydrated with an acid chloride to provide the compound of formula XXX(b). Compounds of formula XXX(b)

wherein R 336 comprises an polymeric substituent group are particularly preferred.

XXXIII

XXX(a) XXX(b)

[0115] Compounds of formula XXXI wherein R³⁰ includes the polymeric substituent L(R)_n may be prepared by reaction of a polymeric substituent acid chloride such as (XXXV) with the appropriate furan in the presence of a Lewis acid catalyst (such as tin tetrachloride):

Fulgimide compounds of formula XXX in which

A' is the group of formula XXXVI may be prepared by reaction of an amine with a free nucleophilic group such as 4-hydroxyaniline with the corresponding fulgide of formula XXX where A' is oxygen to provide the intermediate fulgimide having a free nucleophilic group such as hydroxy (e.g. formula XXXVII) and reaction of the free nucleophilic of the fulgimide with (i) a polymeric substituent acid chloride or anhydride (ii) functional groups suitable to allow the growth of a polymer directly from the fulgimide. This might be a group suitable for RAFT, ATRP or iniferter control radical polymerization to provide the polymeric substituent substituted fulgimide of (e.g. formula XXXVI)

XXXVI

XXXVII [0116] Examples of azo dyes include compounds of formula XL

XL wherein: one of R⁴⁰ and R⁴¹ is a polymeric substituent and the other is selected from the group consisting of hydrogen, Ci to C₆ alkyl, Ci to C₆ alkoxy, -NR⁴²R⁴³ wherein R⁴² and R⁴³ are as defined for R²⁶ and R²⁷ aryl (such as phenyl) aryl substituted with one or more substituents selected from Ci to C₆ alkyl and Ci to C₆ alkoxy, substituted Ci to C₆ alkyl wherein the substituent is selected from aryl and Ci to C₆ alkoxy, substituted Ci to C₆ alkoxy wherein the substituent is selected from Ci to C₆ alkoxy aryl and aryloxy.

[0117] The photochromic moiety may also be selected from diarylperfluorocyclopentenes including compounds of formula XXXV and XXXVI:

wherein

R³⁴, R³⁵, R³⁶, R³⁷ independently represents a Ci to C₄ alkyl, phenyl or phen(Ci to

C₄) alkyl or one of and R³⁴ ,R³⁵ R³⁶, R³⁷ is hydrogen and the others is one of the aforementioned groups; and wherein at least one of Q , R³⁴, R³⁵ , R³⁶ and R³⁷comprises the groupL(R)_n.

Specific Examples of polymeric photochromies of the invention are included in Tables 1 - 5.

Table 1

AN = acrylonitrile, VC = vinylidene chloride, AMA = allyl methacrylate, BA = butyl acrylate, MA = methyl acrylate Table 2

Table 3

Table 4

Table 5

[0118] The compounds of the invention may contain one or more photochromic dyes. The compounds of the invention may also be used in mixtures with conventional photochromies.

[0119] The use of compounds of the invention allows the fatigue to be improved and preferably the fade speed of the photochromic to be changed without changing its colour. Thus, it allows the tuning of fade speed for different coloured dyes. This is important to get a consistent colour when fading occurs. Thus, if a blue dye of a particular speed is needed, modification can be made to include a polymeric substituent of an appropriate length in accordance with the invention.

[0120] The photochromic compounds (or compositions containing same) of the present invention may be applied or incorporated into a host material by methods known in the art. Such methods include dissolving or dispersing the compound in the host material. The compound may be melt blended with the host matrix.

[0121] The compounds of the invention may be incorporated in polymerizable compositions used to form the host matrix so that they become bound within the polymerized host. In one embodiment of the invention the photochromic compound of the invention comprises a group which is reactive with the polymerizable composition during curing. For example, the polymerizable group may be an unsaturated group which becomes tethered to the host polymer during curing of the host composition. The group may be an alcohol, acid, amine or other group for reacting with co-reactive functional groups in a host monomer. In this embodiment the compound of the invention becomes chemically bound with the polymeric substituent forming a tether bound (particularly by covalent bonds) to the host. Reactions between the terminal group of the polymeric substituent of a photochromic compound are described in our co pending Australian provisional patent application No. 2004902302.

[0122] In one aspect the invention provides a photochromic article having a Tg of at least 5O⁰C, comprising a polymeric matrix formed by polymerization of a monomer composition comprising a photochromic monomer comprising a photochromic moiety which is tethered to a reactive group which has undergone reaction to become part of the polymer via a pendant polymeric substituent comprising a gas barrier polymer and a polymeric group of low Tg polymeric unit comprising at least 3 and more preferably at least 5 and more preferably at least 7 monomeric units.

[0123] In the preferred embodiment the low Tg polymeric group provides a rate of fade of the photochromic which is significantly increased compared with the corresponding composition comprising an electrically equivalent dye without the low Tg polymeric group. Generally the photochromic article is solid at ambient temperature and typically it has a Tg of at least 50^QC, preferably at least 70^QC, and most preferably at least 8O⁰C.

[0124] The advantage of the photochromic compound of the invention is that the polymeric substituent chain may coil about or near the photochromic group to provide nanoencapsulation providing a gas barrier to the photochromic moiety and reducing the degradation caused by agents such as radical and oxygen. The nature of the gas barrier polymer may be chosen according to the relative population of different degrading components in the host matrix. For example, if the host is relatively oxygen permeable then a significant chain length of an efficient oxygen barrier polymer may be desired particularly is long term resistance to fatigue is required. For example, it may be preferred to use a polyvinyl acetate (partly or fully converted to polyvinyl alcohol) a poly acrylonitrile. The chain length of oxygen barrier polymer may be of molecular weight of 1000 or more.

[0125] The presence of low Tg substituent may simultaneously facilitate more rapid conversion between ring-open and ring-closed forms. The polymeric substituent chains may provide a low Tg nanoenvironment or otherwise favourably alter the local environment. Accordingly, for faster colouration and fade, it is preferred that the polymeric substituent attached to the photochromic compound of the invention has a relatively low Tg. For example, the Tg is preferably less than 25⁰C. More preferably the compounds of the invention are non-crystalline at room temperature and more preferably liquid at room temperature, this making them easier to disperse and dissolve in the monomer composition.

[0126] Alternatively, the compound of the invention may be non-reactive with the host and/or the polymerizable composition for forming the host. In this embodiment the compound of the invention may become incorporated in the host before, during or after curing of a polymerizable composition used to form the host.

[0127] The photochromic compound of the invention may be incorporated by imbibation into the host material. It may also be introduced by immersion, thermal transfer or coating and incorporation of the photochromic layer as part of a separation layer between adjacent layers of the host material. The term "imbibation" or "imbibe" is intended to mean and include diffusion of the photochromic compound alone into the host material, solvent assisted diffusion, absorption of the photochromic compound into a porous polymer, vapor phase transfer, and other such transfer mechanisms. For example:

(a) The photochromic compounds (or compositions containing same) of the present invention can be mixed with a polymerizable composition that, upon curing, produces an optically clear polymeric host material and the polymerizable composition can be cast as a film, sheet or lens, or injection molded or otherwise formed into a sheet or lens; (b) The photochromic compounds of the present invention can be dissolved or dispersed in water, alcohol or other solvents or solvent mixtures and then imbibed into the solid host material by immersion for several minutes to several hours, e.g. 2-3 minutes to 2-3 hours for the host material in a bath of such solution or dispersion. The bath is conventionally at an elevated temperature, usually in the range of 5O⁰C to 95⁰C. Thereafter, the host material is removed from the bath and dried;

(c) The photochromic compounds (and compositions containing the same) may also be applied to the surface of the host material by any convenient manner, such as spraying, brushing, spin-coating or dip-coating from a solution or dispersion of the photochromic material in the presence of a polymeric binder. Thereafter, the photochromic compound is imbibed by the host material by heating it, e.g. in an oven, for from a minute to several hours at temperatures in the range of from 8O⁰C to 18O⁰C;

(d) In a variation of the above imbibation procedure, the photochromic compound or composition containing the same can be deposited onto a temporary support, or fabric, which is then placed in contact with host material and heated, e.g. in an oven;

(e) The photochromic compounds can be dissolved or dispersed in a transparent polymeric material which can be applied to the surface of the host in the form of a permanent adherent film or coating by any suitable technique such as spraying, brushing, spin-coating or dip-coating;

(f) The photochromic compounds can be incorporated or applied to a transparent polymeric material by any of the above mentioned methods, which can then be placed within the host material as a discrete layer intermediate to adjacent layers of a host material (s);

(g) The photochromic adduct of the invention may be incorporated into a dye composition by ball milling with a carrier to disperse it in a binder matrix. Such a composition may be used as an ink, for example in ink jet printing and suitable (PC) moieties may be chosen to allow security markings on documents to be visible on exposure to UV light used in photocopy;

(h) The photochromic compound may be compounded with suitable resins and the resin melted to shape it to form a film, for example by blow moulding or to form more complex extruded shapes, e.g. by injection moulding and/or blown structures. [0128] The transfer method is described, inter alia, in the documents U.S. Pat. Nos. 4,286,957 and 4,880,667. In this technique, a surface of the transparent polymer substrate is coated with a layer of a varnish containing the photochromic substance to be incorporated. The substrate, thus coated, is then treated thermally in order to cause the photochromic substance to migrate into the substrate.

[0129] Examples of host materials that may be used with the photochromic compounds of the present invention include polymers, i.e., homopolymers and copolymers of polyol(allyl carbonate) monomers, homopolymers and copolymers of polyfunctional acrylate monomers, polyacrylates, poly(alkylacrylates) such as poly(methylmethacrylate), cellulose acetate, cellulose triacetate, celluslose acetate propionate, cellulose acetate butyrate, polyvinyl acetate), poly(vinylalcohol), poly(vinylchloride), poly(vinlylidene chloride), polyurethanes, polycarbonates, poly(ethylene-terephthalate), polystyrene, copoly(styrene-methylmethacrylate), copoly(styrene-acrylateonitrile), poly(vinylbutryl), and homopolymers and copolymers of diacylidene pentaerythritol, particularly copolymers with polyol(allylcarbonate) monomers, e.g. diethylene glycol bis(allyl carbonate), and acrylate monomers. Transparent copolymers and blends of the transparent polymers are also suitable as host materials.

[0130] The host material may be an optically clear polymerized organic material prepared from a polycarbonate resin, such as the carbonate-linked resin derived from bisphenol-A and phosgene which is sold under the trademark LEXAN; a poly(methylmethacrylate), such as the material sold under the trademark PLEXIGLAS; polymerizates of a polyol(allyl carbonate), especially diethylene glycol bis(allyl carbonate), which is sold under the trademark CR-39, and its copolymers such as copolymers with vinyl acetate, e.g. copolymers of from about 80 - 90 percent diethylene glycol bis(allyl carbonate) and 10 - 20 percent vinyl acetate, particularly 80 - 85 percent of the bis(allyl carbonate) and 15 - 20 percent vinyl acetate, cellulose acetate, cellulose propionate, cellulose butyrate, polystyrene and copolymers of styrene with methyl methacrylate, vinyl acetate and acrylonitrile, and cellulose acetate butyrate. [0131] Polyol (ally! carbonate) monomers which can be polymerised to form a transparent host material are the allyl carbonates of linear or branched aliphatic glycol bis(allyl carbonate) compounds, or alkylidene bisphenol bis(allyl carbonate) compounds. These monomers can be described as unsaturated polycarbonates of polyols, e.g. glycols. The monomers can be prepared by procedures well known in the art, e.g. US Pat. Nos. 2,370,567 and 2,403,113. The polyol (allyl carbonate) monomers can be represented by the graphic formula:

wherein R is the radical derived from an unsaturated alcohol and is commonly an allyl or substituted allyl group, R' is the radical derived from the polyol, and n is a whole number from 2-5, preferably 2. The allyl group (R) can be substituted at the 2 position with a halogen, most notably chlorine or bromine, or an alkyl group containing from 1 to 4 carbon atoms, generally a methyl or ethyl group. The R group can be represented by the graphic formula:

R.

H₂C=C-CH₂ wherein R₀ is hydrogen, halogen, or a Ci-C₄ alkyl group. Specific examples of R include the groups: ally 2-chloroallyl, 2-bromoallyl, 2-fluoroallyl, 2-methylallyl, 2-ethylallyl, 2- isopropylallyl, 2-n-propylallyl, and 2-n-buylallyl. Most commonly R is the allyl group:

H₂C=CH-CH₂ —

R' is the polyvalent radical derived from the polyol, which can be an aliphatic or aromatic polyol that contains 2, 3, 4 or 5 hydroxy groups. Typically, the polyol contains 2 hydroxy groups, i.e. a glycol or bisphenol. The aliphatic polyol can be linear or branched and contain from 2 to 10 carbon atoms. Commonly, the aliphatic polyol is an alkylene glycol having from 2 to 4 carbon atoms or a poly(C₂-C₄) alkylene glycol, i.e. ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, or diethylene glycol, triethylene glycol, etc. [0132] In a further embodiment, the invention provides a photochromic article comprising a polymeric organic host material selected from the group consisting of poly(methyl methacrylate), poly(ethylene glycol bismethacrylate), poly(ethoxylated bisphenol-A dimethacrylate), thermoplastic polycarbonate, polyvinyl acetate), polyvinylbutyral, polyurethane, and polymers of members of the group consisting of diethylene glycol bi(allylcarbonate) monomers, diethylene glycol dimethacrylate monomers, ethoxylated phenol bismethylacrylate monomers, diisopropenyl benzene monomers and ethoxylated trimethylol propane triacrylate monomers, and a photochromic amount of a compound of the invention.

[0133] The polymeric organic host material is selected from the group consisting of polyacrylates, polymethacrylates, poly(Ci-Ci₂) alkyl methacrylates, polyoxy(alkylene methacrylates), poly(alkoxylates phenol methacrylates), cellulose acetates, cellulose triacetate, cellulose acetate propionate, cellulose acetate butyrate, polyvinyl acetate), polyvinyl alcohol), polyvinyl chloride) poly(vinylidene chloride), thermoplastic polycarbonates, polyesters, polyurethanes, polythiourethanes, poly(ethylene terephthalate), polystyrene, poly(alpha methylstyrene), copoly(styrene- methylmethacrylate), copoly(styrene-acrylonitrile), polyvinylbutyral and polymers of members of the group consisting of polyol(allyl carbonate) monomers, polyfunctional acrylate monomers, polyfunctional methylacrylate monomers, diethylene glycol dimethacrylate monomers, diisopropenyl benzene monomers, alkoxylates polyhydric alcohol monomers and diallylidene pentaerythritol monomers.

[0134] The photochromic article may comprise a polymeric organic material which is a homopolymer or copolymer of monomer(s) selected from the group consisting of acrylates, methacrylates, methyl mathacrylate, ethylene glycol bis methacrylate, ethoxylated bisphenol-A dimethacrylate, vinyl acetate, vinylbutyral, urethane, thiourethane, diethylene glycol bis(allyl carbonate), diethylene glycol dimethacrylate, diisopropenyl benzene, and ethoxylated trimethyl propane triacrylates. [0135] The photochromic composition of the invention may contain the photochromic compound in a wide range of concentrations depending on the type of photochromic moiety and its intended application. For example, in the case of inks in which high colour intensity is required a relatively high concentration of up to 30 wt% photochromic may be required. On the other hand it may be desirable in some cases such as optical articles to use photochromies in very low concentrations to provide a relatively slight change in optical transparency on irradiation. For example, as low as 0.01 mg/g of host resin may be used. Generally the photochromic resin will be present in an amount of from 0.001 wt% of host resin up to 30 wt% of host resin. More preferably the photochromic compound will be present in an amount of from 0.001 to 10 wt% of host matrix and still more preferably from 0.005 to 10 wt% of host matrix.

[0136] The photochromic article may contain the photochromic compound in an amount of from 0.05 to 10.0 milligram per square centimetre of polymeric organic host material surface to which the photochromic substance(s) is incorporated or applied.

[0137] The compounds of the invention may be used in those applications in which the organic photochromic substances may be employed, such as optical lenses, e.g. vision correcting ophthalmic lenses and piano lenses, face shields, goggles, visors, camera lenses, windows, mirrors, automotive windows, jewellery, aircraft and automotive transparencies, e.g. T-roofs, sidelights and backlights, plastic films and sheets, textiles and coatings, e.g. coating compositions and inks, cosmetics, data storage devices, optical switching devices. As used herein, coating compositions include polymeric coating composition prepared from materials such as polyurethanes, epoxy resins and other resins used to produce synthetic polymers; paints, i.e., a pigmented liquid or paste used for the decoration, protection and/or the identification of a substrate; and inks, i.e., a pigmented liquid or paste used for writing and printing on substrates, which include paper, glass, ceramics, wood, masonry, textiles, metals and polymeric organic materials. Coating compositions may be used to produce verification marks on security documents, e.g. documents such as banknotes, passport and driver' licenses, for which authentication or verification of authenticity may be desired. Security documents, for indicating exposure to light during photocopying.

[0138] The invention will now be described with reference to the following examples. It is to be understood that the examples are provided by way of illustration of the invention and that they are in no way limiting to the scope of the invention.

[0139] Examples of host materials that may be used with the photochromic compounds of the present invention include polymers, i.e., homopolymers and copolymers of polyol(allyl carbonate) monomers, homopolymers and copolymers of polyfunctional acrylate monomers, polyacrylates, poly(alkylacrylates) such as poly(methylmethacrylate), cellulose acetate, cellulose triacetate, celluslose acetate propionate, cellulose acetate butyrate, polyvinyl acetate), poly(vinylalcohol), poly(vinylchloride), poly(vinlylidene chloride), polyurethanes, polycarbonates, poly(ethylene-terephthalate), polystyrene, copoly(styrene-methylmethacrylate), copoly(styrene-acrylateonitrile), poly(vinylbutryl), and homopolymers and copolymers of diacylidene pentaerythritol, particularly copolymers with polyol(allylcarbonate) monomers, e.g. diethylene glycol bis(allyl carbonate), and acrylate monomers. Transparent copolymers and blends of the transparent polymers are also suitable as host materials.

[0140] The host material may be an optically clear polymerized organic material prepared from a polycarbonate resin, such as the carbonate-linked resin derived from bisphenol-A and phosgene which is sold under the trademark LEXAN; a poly(methylmethacrylate), such as the material sold under the trademark PLEXIGLAS; polymerizates of a polyol(allyl carbonate), especially diethylene glycol bis(allyl carbonate), which is sold under the trademark CR-39, and its copolymers such as copolymers with vinyl acetate, e.g. copolymers of from about 80 - 90 percent diethylene glycol bis(allyl carbonate) and 10 - 20 percent vinyl acetate, particularly 80 - 85 percent of the bis(allyl carbonate) and 15 - 20 percent vinyl acetate, cellulose acetate, cellulose propionate, cellulose butyrate, polystyrene and copolymers of styrene with methyl methacrylate, vinyl acetate and acrylonitrile, and cellulose acetate butyrate. [0141] Polyol (ally! carbonate) monomers which can be polymerised to form a transparent host material are the allyl carbonates of linear or branched aliphatic glycol bis(allyl carbonate) compounds, or alkylidene bisphenol bis(allyl carbonate) compounds. These monomers can be described as unsaturated polycarbonates of polyols, e.g. glycols. The monomers can be prepared by procedures well known in the art, e.g. US Pat. Nos. 2,370,567 and 2,403,113. The polyol (allyl carbonate) monomers can be represented by the graphic formula:

R.

H₂C=CH-CH₂ —

R' is the polyvalent radical derived from the polyol, which can be an aliphatic or aromatic polyol that contains 2, 3, 4 or 5 hydroxy groups. Typically, the polyol contains 2 hydroxy groups, i.e. a glycol or bisphenol. The aliphatic polyol can be linear or branched and contain from 2 to 10 carbon atoms. Commonly, the aliphatic polyol is an alkylene glycol having from 2 to 4 carbon atoms or a poly(C₂-C₄) alkylene glycol, i.e. ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, or diethylene glycol, triethylene glycol, etc. [0142] In a further embodiment, the invention provides a photochromic article comprising a polymeric organic host material selected from the group consisting of poly(methyl methacrylate), poly(ethylene glycol bismethacrylate), poly(ethoxylated bisphenol-A dimethacrylate), thermoplastic polycarbonate, polyvinyl acetate), polyvinylbutyral, polyurethane, and polymers of members of the group consisting of diethylene glycol bi(allylcarbonate) monomers, diethylene glycol dimethacrylate monomers, ethoxylated phenol bismethylacrylate monomers, diisopropenyl benzene monomers and ethoxylated trimethylol propane triacrylate monomers, and a photochromic amount of a compound of the invention.

[0143] The polymeric organic host material is selected from the group consisting of polyacrylates, polymethacrylates, poly(Ci-Ci₂) alkyl methacrylates, polyoxy(alkylene methacrylates), poly(alkoxylates phenol methacrylates), cellulose acetates, cellulose triacetate, cellulose acetate propionate, cellulose acetate butyrate, polyvinyl acetate), polyvinyl alcohol), polyvinyl chloride) poly(vinylidene chloride), thermoplastic polycarbonates, polyesters, polyurethanes, polythiourethanes, poly(ethylene terephthalate), polystyrene, poly(alpha methylstyrene), copoly(styrene- methylmethacrylate), copoly(styrene-acrylonitrile), polyvinylbutyral and polymers of members of the group consisting of polyol(allyl carbonate) monomers, polyfunctional acrylate monomers, polyfunctional methylacrylate monomers, diethylene glycol dimethacrylate monomers, diisopropenyl benzene monomers, alkoxylates polyhydric alcohol monomers and diallylidene pentaerythritol monomers.

[0144] The photochromic article may comprise a polymeric organic material which is a homopolymer or copolymer of monomer(s) selected from the group consisting of acrylates, methacrylates, methyl mathacrylate, ethylene glycol bis methacrylate, ethoxylated bisphenol-A dimethacrylate, vinyl acetate, vinylbutyral, urethane, thiourethane, diethylene glycol bis(allyl carbonate), diethylene glycol dimethacrylate, diisopropenyl benzene, and ethoxylated trimethyl propane triacrylates. [0145] The photochromic composition of the invention may contain the photochromic compound in a wide range of concentrations depending on the type of photochromic moiety and its intended application. For example, in the case of inks in which high colour intensity is required a relatively high concentration of up to 30 wt% photochromic may be required. On the other hand it may be desirable in some cases such as optical articles to use photochromies in very low concentrations to provide a relatively slight change in optical transparency on irradiation. For example, as low as 0.01 mg/g of host resin may be used. Generally the photochromic resin will be present in an amount of from 0.001 wt% of host resin up to 30 wt% of host resin. More preferably the photochromic compound will be present in an amount of from 0.001 to 10 wt% of host matrix and still more preferably from 0.005 to 10 wt% of host matrix.

[0146] The photochromic article may contain the photochromic compound in an amount of from 0.05 to 10.0 milligram per square centimetre of polymeric organic host material surface to which the photochromic substance(s) is incorporated or applied.

[0147] The compounds of the invention may be used in those applications in which the organic photochromic substances may be employed, such as optical lenses, e.g. vision correcting ophthalmic lenses and piano lenses, face shields, goggles, visors, camera lenses, windows, mirrors, automotive windows, jewellery, aircraft and automotive transparencies, e.g. T-roofs, sidelights and backlights, plastic films and sheets, textiles and coatings, e.g. coating compositions and inks, cosmetics, data storage devices, optical switching devices. As used herein, coating compositions include polymeric coating composition prepared from materials such as polyurethanes, epoxy resins and other resins used to produce synthetic polymers; paints, i.e., a pigmented liquid or paste used for the decoration, protection and/or the identification of a substrate; and inks, i.e., a pigmented liquid or paste used for writing and printing on substrates, which include paper, glass, ceramics, wood, masonry, textiles, metals and polymeric organic materials. Coating compositions may be used to produce verification marks on security documents, e.g. documents such as banknotes, passport and driver' licenses, for which authentication or verification of authenticity may be desired. Security documents, for indicating exposure to light during photocopying.

[0148] The compounds of the invention have an improved fatigue resistance (that is they have a longer lifetime) when compared with the corresponding unsubstituted photochromic. Generally the light exposure time required for compounds of the present invention to cause 50% fatigue will be at least 20%, more preferably at least 50 and most preferably at least 100% longer than the corresponding unsubstituted dye.

[0149] The invention will now be described with reference to the following examples. It is to be understood that the examples are provided by way of illustration of the invention and that they are in no way limiting to the scope of the invention.

Examples

Comparative Example 1

Spiropyran control compound

[0150] The hydroxyethyl-functionalised spiropyran, 1 , 2-(3',3'-dimethyl-6-nitro-3'/-/- spiro[chromene-2,2'-indol]-1 '-yl)-ethanol, was synthesised according to the literature procedure: F. M. Raymo and S. Giordani, J. Am. Chem. Soc, 2001 , 123, 4651 -4652.

[0151] To a solution of the hydroxyethyl-functionalised spiropyran, 1 , (0.5 g, 1.42 mmol) in dry dichloromethane (20 ml_) was added triethylamine (0.216 g, 2.13 mmol, 0.30 ml_) in one portion, under a nitrogen atmosphere. Acetyl chloride (0.111 g, 1.42 mmol, 0.10 ml_) was then added dropwise via syringe, with stirring. The mixture was stirred at room temperature for 15 minutes and the solvent then evaporated in vacuo. The residue was purified by column chromatography (silica gel, diethyl ether/hexane, 1 :1 ) giving the product, CE1 , as a pale yellow solid (0.473 g, 84%). ¹H NMR (400 MHz, de-acetone) δ 8.15 (d, 1 H), 8.05 (del, 1 H), 7.23-7.13 (m overlap, 3H), 6.85 (m, 2H), 6.76 (d, 1 H), 6.09 (d, 1 H), 4.22 (t, 2H), 3.55 (m, 1 H), 3.44 (m, 1 H), 1.95 (s, 3H), 1.29 (s, 3H), 1.18 (s, 3H).

Example 1

Spiropyran end-functionalised poly(acrylonitrile-co-butyl acrylate) conjugates via ATRP polymerisation

Step i

[0152] To a solution of the hydroxyethyl-functionalised spiropyran, 1 , (2.0 g, 5.67 mmol) in dry dichloromethane (20 ml_) was added triethylamine (1.18 ml_, 8.51 mmol) in one portion, under a nitrogen atmosphere. 2-Bromoisobutyryl bromide (0.70 ml_, 5.67 mmol) was then added dropwise via syringe, with stirring. The mixture was stirred at room temperature for 1 hour and then filtered through a plug of silica gel, eluting with diethyl ether. The solvent was evaporated in vacuo giving the crude product as a red tar. Recrystallisation from ether/heptane by slow and partial evaporation of the solvent gave the product macroinitiator, 2, as a pale yellow crystalline solid (1.85 g, 65%). ¹H NMR (400 MHz, CDCI₃) δ 8.02 (m, 2H), 7.21 (t, 1 H), 7.09 (d, 1 H), 6.92 (m, 2H), 6.76 (d, 1 H), 6.70 (d, 1 H), 6.00 (d, 1 H), 4.31 (m, 2H), 3.58 (m, 1 H), 3.46 (m, 1 H), 1.90 (s, 3H, overlap), 1.89 (s, 3H, overlap), 1.28 (s, 3H), 1.18 (s, 3H).

Step 2

carbonate

Example 1(A, B and C) [0153] A stock solution containing acrylonitrile (7.46 ml_) and n-butyl acrylate (4.08 ml_) was made up to a volume of 25 ml_ with ethylene carbonate. An aliquot (5.7 ml_) was added to each of three ampoules containing the spiropyran functionalised ATRP macroinitiator, 2, (0.081 g, 0.162 mmol), copper(l) chloride (0.016 g, 0.162 mmol) and 4,4'-dinonyl-2,2'-bipyridine (0.132 g, 0.323 mmol). The ampoules were then degassed on a vacuum line with four freeze/pump/thaw cycles, sealed and then heated in a constant temperature oil bath.

1 A: heated at 7O⁰C for 19 hours.

1 B: heated at 7O⁰C for 29 hours and 5 minutes.

1 C: heated at 9O⁰C for 19 hours and 45 minutes.

[0154] To each ampoule was added DMF (5 ml_) and the mixture added dropwise to 15% aqueous methanol (250 ml_) with vigorous stirring. The mixture was allowed to settle and the cloudy supernatant decanted. The solid was washed with methanol with stirring and then filtered. The solid residue was re-dissolved in DMF (5 ml_) and product precipitated again by dropwise addition into methanol (250 ml_) with stirring. The purified dye- polymer conjugates were isolated by filtration and dried in a vacuum oven at 4O⁰C for several hours.

a Molecular weight based on microanalysis and ¹H NMR spectrum integrations for n-butyl acrylate OCH₂ peak. Example 2

Copolymerisation of acrylonitrile, butyl acrylate and spiropyran acrylate monomer by ATRP polymerisation

Step 1

[0155] The spiropyran acrylate monomer was synthesised by the procedure outlined in Comparative Example 1 using acryloyl chloride in place of acetyl chloride. Analysis by ¹H NMR gave a spectrum consistent with the molecular structure.

Step 2

[0156] Acrylonitrile (0.3656 g, 0.0068894 mol, 0.454 ml), butyl acrylate (0.3154 g, 2.461 x 10^"3 mol, 0.353 ml), benzyl 2-bromoisobutyrate initiator (0.0127 g, 4.921 x 10^"5 mol), spiropyran acrylate monomer (0.20 g, 4.921 x 10^"4 mol), copper(l) bromide (0.0071 g, 4.95 x 10^"5 mol), 4,4'-dinonyl-2,2'-bipyridine (0.0402 g, 9.842 x 10^"5 mol) and ethylene carbonate (2 ml) were combined in an ampoule and degassed with 4 freeze/thaw cycles under high vacuum. The ampoule was then heated in a thermostat controlled oil bath at 9O⁰C for 12 hours. The mixture was precipitated into methanol and the solid collected, re- dissolved in a small amount of acetone and precipitated in methanol by slow and partial evaporation of the solvent in air. The small amount of supernatant liquid remaining (approximately VA of initial volume) was carefully decanted and the remaining solid dried in a vacuum oven at 4O⁰C. Analysis by ¹H NMR gave an average molecular weight of 5,718 (referenced to benzyl-CH₂ of initiator moiety), with average numbers of monomer units for acrylonitrile, butyl acrylate and the spiropyran acrylate being 54.4, 13.1 and 2.4 respectively. Average molecular weight per spiropyran unit is 2,383.

Example 3

Spiropyran end-functionalised poly(vinylidene chloride-co-methyl acrylate) conjugate via RAFT polymerisation

Step 1

[0157] 1 -Butanetiol (1.90 g, 2.25 ml) and carbon disulfide (3.2 g, 2.53 ml) were dissolved in chloroform (30 ml) and triethylamine (5.9 ml) then added dropwise. The mixture was stirred at room temperature for 40 minutes then a solution of 4-(chloromethyl)benzoic acid (3.0 g) and triethylamine (2.5 ml) in chloroform added dropwise. Stirring at room temperature was continued overnight after which iodomethane (0.25 ml) was added, the mixture stirred for an additional 60 minutes. The solution was washed with dilute HCI and brine and then dried with MgSO₄ and solvent evaporated, giving a yellow solid. The solid was washed several times with hexane, filtered and dried in air, giving the pure compound (4.2 g). Analysis by ¹H and ¹³C NMR gave spectra consistent with the molecular structure.

Step 2

[0158] The product from Step 1 ( 1.013 g, 3.37 mmol) was dissolved in dry dichloromethane (25 ml) with 2 drops of DMF, under nitrogen. Oxalyl chloride (1.284 g, 10.11 mmol, 0.87 ml) was added in one portion and the mixture stirred at room temperature for 45 minutes. The solvent and excess reagent was evaporated in vacuo. Trace amounts of oxalyl chloride was removed by re-dissolving the residue in dichloromethane and once again removing the solvent by evaporation in vacuo. The acid chloride product was used immediately by adding it (0.967 g) to a solution of hydroxyethyl-functionalised spiropyran, 1 (see CE1 ), and triethylamine (0.63 ml) in dry diethyl ether (20 ml), under nitrogen. The mixture was stirred at ambient temperature for 1 hour and the solvent evaporated. The residue was dissolved in dichloromethane and washed with dilute aqueous NaHCO₃, dilute HCI, water and brine, then dried with MgSO₄. The solvent was evaporated and the resulting oil triturated with a small amount of diethyl ether causing precipitation of the pure product (0.938 g). Analysis by ¹H gave a spectrum consistent with the molecular structure.

Step 3

Example 3

[0159] The spiropyran functionalised RAFT agent from Step 2 (0.1004 g, 0.158 mmol) was added to a small Schlenk flask fitted with a Young tap, together with vinylidene chloride (1.9388 g, 0.02 mol, 1.6 ml), methyl acrylate (0.5902 g, 5.00 mol, 0.45 ml), AIBN (0.0044 g, 0.0268 mmol) and benzene (3.32 ml). The mixture was degassed with 4 freeze/pump/thaw cycles on a high vacuum line, then heated at 7O⁰C in a thermostat controlled oil bath for 20 hours. It was then poured into chloroform (ca. 50 ml) and slowly evaporated to remove unreacted monomer. The solid was then dissolved in a minimal amount of chloroform and precipitated in an excess of methanol with stirring. This gave a gummy solid and a milky supernatant liquid. The solid was collected and re-dissolved in chloroform, then allowed to slowly evaporate in a shallow dish, giving an orange film. Analysis by quantitative ¹³C NMR (500 MHz, CDCI₃, 3 wt% Cr(acac)₃) gave an approximate molecular weight of 14,080. Example 4

Spiropyran mid-functionalised poly(acrylonitrile-co-allyl methacrylate) conjugate via ATRP polymerisation

solvent acetone

[0160] The spiropyran difunctional ATRP macroinitiator was synthesised from hydroxyethyl-functionalised spiropyran 1 using the procedure outlined in Malic et al., Macromolecules, 2008, 41, 1206. Two ampoules containing Spiropyran difunctional ATRP macroinitiator (0.050 g, 6.358 x 10^"5 mol), copper(l) bromide (0.0182 g, 1.272 x 10^"4 mol), 4,4'-dinonyl-2,2'- bipyridine (0.1039 g, 2.543 x 10^"4 mol), acrylonitrile (0.67 ml_, 0.5397 g, 1.017 x 10^"2 mol), allyl methacrylate (0.34 ml_, 0.3208 g, 2.543 x 10^"3 mol) and acetone (1 ml_) were prepared and degassed with 4 freeze/pump/thaw cycles under high vacuum, then heated in a thermostat controlled constant temperature oil bath. Ampoule 1 was heated at 5O⁰C for 3 hours and 40 minutes, whilst ampoule 2 was heated for 6.5 hours at 6O⁰C. Excess monomers were then evaporated by dissolving the bulk mixtures in dichloromethane and passing a stream of nitrogen over the solutions. Removal of the copper catalyst was then effected by passing a solution of the residue in dichloromethane through a short plug of silica gel, finally eluting with diethyl ether. The solvent was evaporated to give the purified polymer conjugates. Analysis of the products by ¹H NMR (CDCI₃) gave average molecular weights of 2,189 (ampoule 1 , m = 6.7, n = 10.5) and 2,887 (ampoule 2, m = 9.5, n = 17). Example 5 - Fatigue Testing

[0161] The products 1A, 1 B and 1 C were incorporated into a test lens matrix (standard methacrylate formulation comprising 1 :4 weight ratio of poly(ethylene glycol)(400) dimethacrylate (PEGDMA) and 2,2'-bis((4-methacryloxyethoxy)phenyl)propane (EBPDMA) with 0.4% azobis(isobutyronitrile) (AIBN)) at a concentration of ca. 1.8 x 10^"7 mol/g. Test lenses were prepared and analysed in the following manner: An amount of dye-polymer conjugate was dissolved in a small amount of acetone and then the appropriate amount of matrix formulation added. The mixture was stirred under vacuum to remove the acetone and then added to the mould. Curing at 8O⁰C for 16 hours gave the lenses which were subjected to fatigue testing by constant UV irradiation for 60 minutes. The irradiation was performed on a light table comprised of a Cary 50 spectrophotometer and a 300 W Oriel xenon lamp as an incident light source. A series of two filters (Edmund Optics WG320 and Edmund Optics band-pass filter U-340) were used to restrict the output of the lamp to a narrow band (350-400 nm). The samples were monitored at their maximum absorbance of the coloured form (582 nm). The results of the fatigue testing are shown in Figure 2.

[0162] Compound 1 A and 3 were incorporated into a slightly modified matrix consisting of 1 :4 weight ratio of poly(ethylene glycol)(400) dimethacrylate (PEGDMA) and ethoxylated bisphenol-A dimethacrylate (average number of EO units = 2.6) with 0.4% azobis(isobutyronitrile) (AIBN)), at a concentration of ca. 1.8 x 10^"7 mol/g. The matrix solution was then cured in a temperature programmable oven set to initially hold the temperature at 4O⁰C for 1 hour and then increase at a rate of 0.2°C/min to 95⁰C where it was held for 3 hours. The test lens was then fatigue tested as described above, the result of which is depicted in Figure 3. Absorbance at 60 minutes irradiation

Example

Figure 2 Figure 3

1A 0.825 0.908

1 B 0.823

1 C 0.764

2 - 0.823 CE1 0.488 0.498

3 - 0.664

[0163] The polymer conjugates were also tested for their fatigue properties in thin films of poly(methyl methacrylate). A stock solution of PMMA (Aldrich, M_w = 120,000) in MEK (15 wt%) was prepared. Solutions of 1 A, 1 B, and 1 C were prepared as follows:

Solution 1

1A: 283 mg (0.030 mmol, Mn = 9,400)

MEK: 1.61 g

15 wt% PMMA in MEK: 8.11 g

Final solids content: 15 wt%

Content of 4a in film: 2.0 x 10^"5 mol/g

Solution 2

1 B: 391 mg (0.035 mmol, Mn = 11 ,100)

MEK: 2.21 g

15 wt% PMMA in MEK: 7.40 g

Final solids content: 15 wt%

Content of 4b in film: 2.3 x 10^"5 mol/g

Solution 3

1 C: 401 mg (0.030 mmol, Mn = 13,400)

MEK: 2.27 g

15 wt% MMA in MEK: 7.32 g

Final solids content: 15 wt% Content of 4c in film: 2.0 x 10^"5 mol/g

[0164] Films were prepared from Solutions 1 -3 in the following manner: A drop of solution (approx. 0.1 ml) was placed on a glass slide. The drop was drawn across the surface of the slide using a 100 μm wire wound bar to create a film of thickness approx. 15 μm after drying. Samples were allowed to dry for 16 h at room temperature and stored in the dark prior to analysis. 8-10 films were prepared from each solution. From these, 3-4 defect-free films were selected for spectroscopic analysis. The films were fatigue tested using the same method as outlined above for test lenses. Results of the fatigue tests are shown in Figure 4 below.

[0165] The above results show clearly the increase in life-time of the photochromic dye through the use of substituents containing gas-barrier polymer. In this case they were polymers containing acrylonitrile or vinylidene chloride. Better fatigue performance was obtained when the dye-polymer conjugates were in a rigid host matrix such as an optical lense matrix although improvement in fatigue was also observed in thin films.

Claims

1. A photochromic polymer for use in a polymeric composition comprising at least one photochromic moiety and at least one substituent comprising a gas barrier polymer selected from the group consisting of polymers of vinyl monomers of chemical formula CH₂=CXY wherein at least one of X and Y is selected from the group consisting of hydroxyl, acetyl, nitrile and chlorine and the other is selected from the group consisting of hydrogen and chlorine and copolymers of said monomer; polyesters and copolymers thereof; and polyamides and copolymers thereof.

2. A photochromic polymer according to claim 1 wherein the gas barrier polymer comprises repeating units selected from the group consisting of acrylonitrile, methacrylonitrile, vinylchloride, vinylidene chloride, vinyl alcohol, vinyl acetate, polyesters and polyamides optionally copolymerized.

3. A photochromic polymer according to claim 1 or claim 2 wherein the photochromic polymer further comprises a polymeric chain comprising a polymer segment having a Tg of less than 25⁰C.

4. A photochromic polymer according to any one of claims 1 to 3 wherein the gas barrier moiety is a polymer comprising at least 5 and preferably at least 10 monomers.

5. A photochromic polymer according to any one of claims 1 to 4 wherein the gas barrier polymeric substituent has a molecular weight of at least 200 and more preferably at least 250.

6. A photochromic polymer according to claim 2 wherein the gas barrier polymer is a copolymer of the vinyl monomer comprising at least one comonomer selected from acrylate and methacrylate comonomers.

7. A photochromic polymer according any one of the previous claims comprising a substituent comprising a gas barrier polymer selected from polyesters prepared by reacting an organic diacid containing at least one active hydrogen group and diglycidyl ether in the presence of an optional catalyst and polyesters prepared by reaction of transesterification resistant diols such as neopentyl glycol or bis-hydroxyl ethyl resorcinol with a suitable diacid.

8. A photochromic polymer according to any one of the previous claims wherein the gas barrier substituent is covalently linked to the photochromic moiety via a linking group.

9. A photochromic polymer according to claim 1 wherein the at least one substituent is selected from the group of formula Na and lib:

wherein in the formula Na to lib:

U is a covalent linker to the polymeric group (Poly) and is a bond or a chain containing up to four units defined by any one of formulae Nc to Hf

Nc

X' is selected from the group consisting of oxygen, sulfur, amino, alkylamino, Ci to C₄ alkylene, Ci to C₄ alkyleneoxy, Ci to C₄alkyleneoxy(Ci to C₄alkyleneoxy) carbonyl (Ci to C₄ alkylene);

Poly is the position of the covalently bonded gas barrier polymer.

10. A photochromic polymer according to claim 9 wherein B comprises a polymer segment of Tg less than 25⁰C.

11. A photochromic polymer according to any one of the previous claims wherein the photochromic moiety is selected from the group consisting of chromenes, spiropyrans, spirooxazines, fulgides, fulgimides, anils, perimidinespirocyclohexadienones, stilbenes, thioindigoids, azo dyes, diarylethenes and diarylperfluorocyclopentenes.

12. A photochromic polymer according to any one of the previous claims wherein the photochromic moiety is selected from chromenes, spiropyrans and spirooxazines.

13. A photochromic polymer according to any one of the previous claims wherein the compound is a copolymer of a monomer comprising a photochromic moiety and a monomer for forming a gas barrier polymer.

14. A photochromic polymer according to claim 19 wherein the copolymer comprises: (i) a vinyl copolymer of at least one vinyl monomer of formula CH₂ = CXY wherein at least one of X and Y is selected from the group consisting of hydroxyl, acetyl, nitrile and chlorine and the other is selected from the group consisting of hydrogen and chlorine; and a vinyl monomer comprising said photochromic moiety;

(ii) a polyester of a diacid monomer with a polyol monomer comprising a photochromic moiety; and

(iii) a polyamide of a diacid monomer with a polyamine monomer comprising a photochromic moiety.

15. A photochromic polymer according to any one of the previous claims wherein the polymer is formed by living free radical polymerization.

16. A photochromic polymeric composition comprising a matrix selected from the group consisting of polymers of Tg of at least 5O⁰C and monomer compositions which on curing provide polymers of Tg of at least 5O⁰C; and a photochromic polymer according to any one of claims 1 to 10.

17. A photochromic composition according to claim 16 wherein the photochromic polymer comprises a functional group which is reactive with the matrix to thereby covalently bond the photochromic polymer to the matrix.

18. A photochromic composition according to claim 16 wherein the photochromic polymer remains unbound to the matrix.

19. A photochromic composition according to claim 16 wherein the photochromic compound is imbibed into a solid polymeric matrix which is at least partly cured.

20. A photochromic composition according to any one of claim 16 to 19 wherein the matrix is selected from the group consisting of homopolymers and copolymers of polyol(allyl carbonate) monomers, homopolymers and copolymers of polyfunctional acrylate monomers, polyacrylates, poly(alkylacrylates), cellulose acetate, cellulose triacetate, cellulose acetate propionate, cellulose acetate butyrate, polyvinyl acetate), poly(vinylalcohol), poly(vinylchloride), poly(vinlylidene chloride), polyurethanes, polycarbonates, poly(ethylene-terephthalate), polystyrene, copoly(styrene- methylmethacrylate), copoly(styrene-acrylonitrile), poly(vinylbutyrl), and homopolymers and copolymers of diacylidene pentaerythritol, and blends of two or more thereof and monomer compositions for preparing such polymers