WO2019079665A1

WO2019079665A1 - Photochromic article and methods of making same

Info

Publication number: WO2019079665A1
Application number: PCT/US2018/056613
Authority: WO
Inventors: Kai C. Su; Leslie F. Stebbins; Brad L. Williams; Sean MOTLEY
Original assignee: Qspex Technologies, Inc.
Priority date: 2017-10-20
Filing date: 2018-10-19
Publication date: 2019-04-25
Also published as: TW201923025A

Abstract

A method of forming a photochromic article includes dissolving a polyurethane host material into 1-methoxy-2-propanol to form a first solution; stirring the first solution; adding a a photochromic dye to a mixture of 1-methoxy-2-propanol and butyl acetate to form a second solution; adding the second solution into the stirred first solution to form a third solution; adding triphenylphosphine into the third solution having the polyurethane host material and the photochromic dye to form a fourth solution; stirring the fourth solution until the fourth solution is a dark color with no undissolved particles; adjusting the stirred fourth solution to a viscosity by the mixture of 1-methoxy-2-propanol and butyl acetate to form a fifth solution; and spraying coat the fifth solution onto a substrate to form the photochromic article. Accordingly, addition of certain anti-oxidants, such as the oxygen scavenger TPP, increases the fade speed of photochromic articles.

Description

PHOTOCHROMIC ARTICLE AND METHODS OF MAKING SAME

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and benefit of U.S. provisional patent application Serial No. 62/574,995, filed October 20, 2017, which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The invention relates to a photochromic article and making methods and applications of the same.

BACKGROUND OF THE INVENTION

The background description provided herein is for the purpose of generally presenting the context of the present invention. The subject matter discussed in the background of the invention section should not be assumed to be prior art merely as a result of its mention in the background of the invention section. Similarly, a problem mentioned in the background of the invention section or associated with the subject matter of the background of the invention section should not be assumed to have been previously recognized in the prior art. The subject matter in the background of the invention section merely represents different approaches, which in and of themselves may also be inventions.

Photochromic lenses are typically made by applying a photochromic coating to a plastic ophthalmic lens or by incorporating a photochromic compound in the lens matrix. The photochromic lens darkens when exposed to ultraviolet (UV) light, allowing the lenses to function as sunglasses, then fades when the UV light is removed.

One common problem associated with the conventional photochromic lenses is long fade time, in which when the wearer goes from outdoors in the sun to indoors, where the light is dimmer, the lenses do not fade immediately, making vision difficult.

Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies.

SUMMARY OF THE INVENTION

One of the objectives of this invention is to provide a photochromic article such as a photochromic lens that solves the aforementioned deficiencies and inadequacies by increasing the fade speed of a photochromic dye, which decreases the amount of time when a user is walking around indoors with dark glasses, making the user able to see better indoors and therefore be safer.

In one aspect, the invention relates to a method of forming a photochromic article. The photochromic article can be a photochromic lens, or a photochromic glass such as building glass, windows and so on.

In one embodiment, the method includes dissolving a first amount of a polyurethane host material into a second amount of l-methoxy-2-propanol (MOP) to form a first solution; stirring the first solution with a stainless- steel propeller; adding a third amount of a

photochromic dye to a mixture of MOP and butyl acetate to form a second solution; adding the second solution into the stirred first solution to form a third solution; adding a fourth amount of triphenylphosphine (TPP) into the third solution having the polyurethane host material and the photochromic dye to form a fourth solution; stirring the fourth solution until the fourth solution is a dark color with no undissolved particles; adjusting the stirred fourth solution to a viscosity of 60 cP by the mixture of MOP and butyl acetate to form a fifth solution; and spraying coat the fifth solution onto a substrate, which is dried, e.g., in a clean room oven, to remove solvent to form the photochromic article.

In one embodiment, the method further includes treating the photochromic article with a hard coat resin for scratch resistance.

In one embodiment, the method further includes treating the photochromic article with an anti-reflective coating.

The photochromic dye comprises a photochromic material thai reversibly changes color upon exposure to an UV light source and changes back to colorless when removed from the UV light source. Accordingly the invention, the photochromic dye can be any photochromic dye.

In one embodiment, the substrate is a flexible or rigid substrate, being made of glass or plastic. In one embodiment, the substrate has a thickness that is constant or varied at different locations thereof.

In one embodiment, the polyurethane host material comprises PE287.

In one embodiment, TPP is about 5-100% of the photochromic dye by weight, and preferably in a range of about 12-60% by weight. In one embodiment, the photochromic dye comprises volcanic grey photochromic dye. In one embodiment, TPP is about 5-15% of the volcanic grey photochromic dye by weight, and preferably about 12% by weight.

In one embodiment, the photochromic dye comprises PI 499.

In one embodiment, TPP is about 30-60% of P1499 by weight, and preferably about 48% by weight.

In one aspect, the invention relates to a method of forming a photochromic article, comprising forming a solution comprising a photochromic dye and TPP, where the

photochromic dye comprises a photochromic material that reversibly changes color upon exposure to an UV light source and changes back to colorless when removed from the UV light source; and coating the solution onto a substrate, which is dried to remove solvent to form the photochromic article.

In one embodiment, the method further comprises treating the photochromic article with a hard coat resin for scratch resistance.

In one embodiment, the method further comprises treating the photochromic article with an anti-reflective coating.

In one embodiment, the solution further comprises a polyurethane host material, MOP, and/or butyl acetate. In one embodiment, the polyurethane host material comprises PE287.

In one embodiment, TPP is about 5-100% of the photochromic dye by weight, and preferably in a range of about 12-60% by weight.

In one embodiment, the photochromic dye comprises volcanic grey photochromic dye, or P1499.

In one embodiment, TPP is about 5-15% of the volcanic grey photochromic dye by weight, and preferably about 12% by weight.

In one embodiment, the solution has a viscosity of about 60 cP.

In one aspect, the invention relates to a photochromic article formed by the above method.

In one embodiment, the photochromic article has a substrate; and a photochromic layer formed of a photochromic dye and TPP on a surface of the substrate, wherein the

photochromic dye comprises a photochromic material that reversibly changes color upon exposure to an UV light source and changes back to colorless when removed from the UV light source. The photochromic article is a photochromic glass, or a photochromic lens.

In one embodiment, the photochromic article further has a hard coat resin layer for scratch resistance.

In one embodiment, the photochromic article further has an anti-reflective coating.

In one embodiment, the photochromic layer further comprises one or more of a hindered amine light stabilizer, an anti-oxidant material, and other stabilizers and additives.

In one embodiment, the photochromic layer further comprises a polyurethane host material.

In one embodiment, the polyurethane host material comprises PE287

In one embodiment, the photochromic dye comprises volcanic grey photochromic dye. In one embodiment, TPP is about 5-15% of the volcanic grey photochromic dye by weight, and preferably about 12% by weight.

In one embodiment, the photochromic dye comprises PI 499.

In one embodiment, the substrate is a flexible or rigid substrate made of glass or plastic. In one embodiment, the substrate has a thickness that is constant or varied at different locations thereof.

These and other aspects of the present invention will become apparent from the following description of the preferred embodiment taken in conjunction with the following drawings, although variations and modifications therein may be affected without departing from the spirit and scope of the novel concepts of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate one or more embodiments of the disclosure and together with the written description, serve to explain the principles of the disclosure.

Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like elements of an embodiment.

FIG. 1 shows schematically a flowchart of forming a photochromic article according to one embodiment of the present invention.

FIG. 2A shows schematically a photochromic article according to one embodiment of the present invention.

FIG. 2B shows schematically a photochromic article according to another embodiment of the present invention.

FIG. 3 shows light transmission vs time of a photochromic lens according to one embodiment of the present invention.

FIG. 4 shows light transmission vs time of a photochromic lens according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals refer to like elements throughout.

The terms used in this specification generally have their ordinary meanings in the art, within the context of the invention, and in the specific context where each term is used.

Certain terms that are used to describe the invention are discussed below, or elsewhere in the specification, to provide additional guidance to the practitioner regarding the description of the invention. For convenience, certain terms may be highlighted, for example using italics and/or quotation marks. The use of highlighting has no influence on the scope and meaning of a term; the scope and meaning of a term is the same, in the same context, whether or not it is highlighted. It will be appreciated that the same thing can be said in more than one way.

Consequently, alternative language and synonyms may be used for any one or more of the terms discussed herein, nor is any special significance to be placed upon whether or not a term is elaborated or discussed herein. Synonyms for certain terms are provided. A recital of one or more synonyms does not exclude the use of other synonyms. The use of examples anywhere in this specification including examples of any terms discussed herein is illustrative only, and in no way limits the scope and meaning of the invention or of any exemplified term. Likewise, the invention is not limited to various embodiments given in this specification.

It will be understood that when an element is referred to as being "on" another element, it can be directly on the other element or intervening elements may be present therebetween. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, third etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the disclosure.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or

"comprising", or "includes" and/or "including" or "has" and/or "having" when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof.

Furthermore, relative terms, such as "lower" or "bottom", "upper" or "top", and "left" and "right", may be used herein to describe one element's relationship to another element as illustrated in the Figures. It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. For example, if the device in one of the figures is turned over, elements described as being on the "lower" side of other elements would then be oriented on "upper" sides of the other elements. The exemplary term "lower", can therefore, encompasses both an orientation of "lower" and "upper", depending of the particular orientation of the figure. Similarly, if the device in one of the figures is turned over, elements described as "below" or "beneath" other elements would then be oriented "above" the other elements. The exemplary terms "below" or "beneath" can, therefore, encompass both an orientation of above and below.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

As used herein, "around", "about" or "approximately" shall generally mean within 20 percent, preferably within 10 percent, and more preferably within 5 percent of a given value or range. Numerical quantities given herein are approximate, meaning that the term "around", "about" or "approximately" can be inferred if not expressly stated.

The description below is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. The broad teachings of the invention can be

implemented in a variety of forms. Therefore, while this invention includes particular examples, the true scope of the invention should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. For purposes of clarity, the same reference numbers will be used in the drawings to identify similar elements. It should be understood that one or more steps within a method may be executed in different order (or concurrently) without altering the principles of the invention.

This invention, in certain aspects, relates to a photochromic article such as a

photochromic lens having a fast fade speed, and a method of making the photochromic article.

Conventionally, photochromic lenses get dark quick when exposed to UV light, but are slow to fade back to their transparent and uncolored state. This can lead to eyeglasses that leave the wearer looking through dark lenses when going indoors. By increasing the fade speed of a photochromic dye, one can decrease the amount of time when a user must be walking around indoors with dark glasses, making the user able to see better indoors, and therefore be safer.

A typical anti-oxidant does not prevent a lens from yellowing during lens processing. If a lens is coated, and not processed immediately with buffer coating and hard coating, the lens would start to yellow. In one embodiment, TPP is added in a host material, which not only reduces the yellowing of the host material, but also visibly increases the fade speed of the photochromic dye and increases transmission in the clear state.

Referring to FIG. 1 now, a flowchart of forming a photochromic article is shown according to one embodiment of the invention. In the exemplary embodiment, the method includes the following steps.

At step 110, a first amount of a polyurethane host material is dissolved into a second amount of MOP to form a first solution.

At step 120, the first solution is stirred, for example, with a stainless- steel propeller, or other stirring means.

At step 130, a third amount of a photochromic dye is added to a mixture of MOP and butyl acetate to form a second solution.

At step 140, the second solution is added into the stirred first solution to form a third solution.

At step 150, a fourth amount of TPP is added into the third solution having the polyurethane host material and the photochromic dye to form a fourth solution.

At step 160, the fourth solution is stirred until the fourth solution is a dark color with no undissolved particles.

At step 170, the stirred fourth solution is adjusted to have a viscosity of 60 cP by the mixture of MOP and butyl acetate to form a fifth solution.

At step 180, the fifth solution is spraying-coated onto a substrate, which is dried, e.g., in a clean room oven, to remove solvent to form the photochromic article.

Further, the method also includes treating the photochromic article with a hard coat resin for scratch resistance.

In addition, the method may include treating the photochromic article with an anti- reflective coating.

In one embodiment, the polyurethane host material comprises PE287 (Huntsman Advanced Materials, The Woodlands, Texas).

The photochromic dye comprises a photochromic material that reversibly changes color upon exposure to an UV light source and changes back to colorless when removed from the UV light source. Accordingly the invention, the photochromic dye can be any photochromic dye.

In one embodiment, the photochromic dye comprises volcanic grey photochromic dye. TPP is about 5-15% of the volcanic grey photochromic dye by weight, and preferably about 12% by weight. In one embodiment, the photochromic dye comprises P1499 (ChromTech PH-1499) photochromic dye. TPP is about 30-60% of P1499 by weight, and preferably about 48% by weight.

In another aspect of the invention, the method of forming a photochromic article includes forming a solution comprising a photochromic dye and TPP; and coating the solution onto a substrate, which is dried to remove solvent to form the photochromic article. The photochromic dye comprises a photochromic material that reversibly changes color upon exposure to an UV light source and changes back to colorless when removed from the UV light source

In one embodiment, the solution has a viscosity of about 60 cP.

In one embodiment as shown in FIG. 2A, the photochromic article has a substrate 210; and a photochromic layer 220 formed of a photochromic dye and TPP on a surface of the substrate 210. In some embodiments, the photochromic layer 220 may further have a polyurethane host material. The polyurethane host material in one embodiment comprises PE287. In certain embodiments, the photochromic layer 220 may also have one or more of a hindered amine light stabilizer, an anti-oxidant material, and other stabilizers and additives.

The photochromic article can be a photochromic glass such as building glass and windows, a photochromic lens, or the likes.

The photochromic dye comprises a photochromic material that reversibly changes color upon exposure to an UV light source and changes back to colorless when removed from the UV light source.

In some embodiments, the photochromic dye comprises volcanic grey photochromic dye. In one embodiment, TPP is about 5-15% of the volcanic grey photochromic dye by weight, and preferably about 12% by weight.

In some embodiments, the photochromic dye comprises P1499. In one embodiment, TPP is about 30-60% of P1499 by weight, and preferably about 48% by weight.

In some embodiments, the substrate 210 is a flexible or rigid substrate made of glass or plastic. In some embodiments, the substrate 210 has a thickness that is constant or varied at different locations thereof. For example, for a photochromic lens, the substrate may be a curved substrate having a thickness that is constant or varied at different locations thereof. For a building window, the substrate may be a flat plate having a thickness that is constant at different locations thereof.

In another embodiment as shown in FIG. 2B, the photochromic article may further have an anti-reflective coating 230 and/or a hard coat resin layer for scratch resistance 240 formed on the photochromic layer 220.

According to embodiments of the invention, addition of certain anti-oxidants, such as the oxygen scavenger TPP, in the photochromic articles significantly increases the fade speed of the photochromic articles.

These and other aspects of the present invention are further described below. Without intent to limit the scope of the invention, exemplary examples, methods and their related results according to the embodiments of the present invention are given below.

EXAMPLE 1

In this exemplary example, about 18 grams of PE287 (Huntsman Advanced Materials, The Woodlands, Texas) are dissolved in about 110 grams l-methoxy-2-propanol (MOP) to form a first solution. The first solution is stirred with a stainless-steel propeller. About 4.4 grams of volcanic grey photochromic dye (Vivimed Labs, Monmouth Junction, New Jersey) are added to an about 50 gram mixture of MOP and butyl acetate to form a second solution. The second solution is added to the first solution to form a third solution. About 0.5 grams of TPP are then added to the third solution having a polyurethane host material of PE287 and a photochromic dye of volcanic grey dye to form a fourth solution. The fourth solution is stirred until the fourth solution is a dark color with no undissolved particles. The stirred fourth solution is then adjusted to a viscosity of about 60 cP by using the mixture of MOP and butyl acetate to form a fifth solution. The fifth solution is spun coat onto a lens substrate, dried in a clean room oven to remove solvent, then allowed to cool. The photochromic lens is then further treated with a hard coat resin for scratch resistance, and possibly further with an anti- reflective coating.

In the example, TPP is about 12% of volcanic grey photochromic dye by weight. The characterization of light transmission vs time for the photochromic lens is shown in FIG. 3, where the light transmission for a control photochromic lens with the volcanic grey

photochromic dye only (without TPP) is also shown for comparison. Clearly, the fade speed of the photochromic lens is significantly increased by adding TPP.

EXAMPLE 2

In this exemplary example, about 18 grams of PE287 are dissolved in about 110 grams l-methoxy-2-propanol (MOP) to form a first solution. The first solution is stirred with a stainless- steel propeller. About 3.2 grams of P1499 (ChromTech PH-1499) photochromic dye are added to an about 50 gram mixture of MOP and butyl acetate to form a second solution. The second solution is added to the first solution to form a third solution. About 1.5 grams of TPP are then added to the third solution having a polyurethane host material of PE287 and a photochromic dye of P1499 to form a fourth solution. The fourth solution is stirred until the fourth solution is a dark color with no undissolved particles. The stirred fourth solution is then adjusted to a viscosity of about 60 cP by using the mixture of MOP and butyl acetate to form a fifth solution. The fifth solution is spun coat onto a lens substrate, dried in a clean room oven to remove solvent, then allowed to cool. The photochromic lens is then further treated with a hard coat resin for scratch resistance, and possibly further with an anti-reflective coating.

In the example, TPP is about 48% of P1499 photochromic dye by weight. The characterization of light transmission vs time for the photochromic lens is shown in FIG. 4, where the light transmission for a control photochromic lens with the P1499 photochromic dye only (without TPP) is also shown for comparison. Obviously, the fade speed of the

photochromic lens is significantly increased by adding TPP.

The foregoing description of the exemplary embodiments of the invention has been presented only for the purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in light of the above teaching.

The embodiments were chosen and described in order to explain the principles of the invention and their practical application so as to enable others skilled in the art to utilize the invention and various embodiments and with various modifications as are suited to the particular use contemplated. Alternative embodiments will become apparent to those skilled in the art to which the present invention pertains without departing from its spirit and scope. Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing description and the exemplary embodiments described therein.

Claims

CLAIMS What is claimed is:

1. A method of forming a photochromic article, comprising:

dissolving a first amount of a polyurethane host material into a second amount of l-methoxy-2-propanol (MOP) to form a first solution;

stirring the first solution;

adding a third amount of a photochromic dye to a mixture of MOP and butyl acetate to form a second solution;

adding the second solution into the stirred first solution to form a third solution; adding a fourth amount of triphenylphosphine (TPP) into the third solution having the polyurethane host material and the photochromic dye to form a fourth solution;

stirring the fourth solution until the fourth solution is a dark color with no undissolved particles;

adjusting the stirred fourth solution to a viscosity by the mixture of MOP and butyl acetate to form a fifth solution; and

spraying coat the fifth solution onto a substrate, which is dried to remove solvent to form the photochromic article.

2. The method of claim 1, further comprising treating the photochromic article with a hard coat resin for scratch resistance.

3. The method of claim 1, further comprising treating the photochromic article with an anti-reflective coating.

4. The method of claim 1, wherein the polyurethane host material comprises PE287.

5. The method of claim 1, wherein TPP is about 5-100% of the photochromic dye by weight, and preferably in a range of about 12-60% by weight.

6. The method of claim 1, wherein the photochromic dye comprises a photochromic material that reversibly changes color upon exposure to an ultraviolet (UV) light source and changes back to colorless when removed from the UV light source.

7. The method of claim 6, wherein the photochromic dye comprises volcanic grey

photochromic dye, or PI 499.

8. The method of claim 7, wherein TPP is about 5-15% of the volcanic grey photochromic dye by weight, and preferably about 12% by weight.

9. The method of claim 7, wherein TPP is about 30-60% of P1499 by weight, and

preferably about 48% by weight.

10. The method of claim 1, wherein the viscosity is about 60 cP.

11. The method of claim 1, wherein the substrate is a flexible or rigid substrate, being made of glass or plastic.

12. The method of claim 17, wherein the substrate has a thickness that is constant or varied at different locations thereof.

13. A photochromic article, being formed by the method of claim 1.

14. The photochromic article of claim 13, being a photochromic lens, or a photochromic glass.

15. A method of forming a photochromic article, comprising:

forming a solution comprising a photochromic dye and triphenylphosphine (TPP), wherein the photochromic dye comprises a photochromic materia] that reversibly changes color upon exposure to an ultraviolet (UV) light source and changes back to colorless when removed from the UV light source; and

coating the solution onto a substrate, which is dried to remove solvent to form the photochromic article.

16. The method of claim 15, further comprising treating the photochromic article with a hard coat resin for scratch resistance.

17. The method of claim 15, further comprising treating the photochromic article with an anti-reflective coating.

18. The method of claim 15, wherein the solution further comprises a polyurethane host material, l-methoxy-2-propanol (MOP), and/or butyl acetate.

19. The method of claim 18, wherein the polyurethane host material comprises PE287.

20. The method of claim 15, wherein TPP is about 5-100% of the photochromic dye by weight, and preferably in a range of about 12-60% by weight.

21. The method of claim 15, wherein the photochromic dye comprises volcanic grey

photochromic dye, or PI 499.

22. The method of claim 21, wherein TPP is about 5-15% of the volcanic grey

photochromic dye by weight, and preferably about 12% by weight.

23. The method of claim 21, wherein TPP is about 30-60% of P1499 by weight, and

preferably about 48% by weight.

24. The method of claim 18, wherein the solution has a viscosity of about 60 cP.

25. A photochromic article, comprising:

a substrate; and

a photochromic layer formed of a photochromic dye and triphenylphosphine (TPP) on a surface of the substrate, wherein the photochromic dye comprises a photochromic material that reversibly changes color upon exposure to an ultraviolet (UV) light source and changes back to colorless when removed from the UV light source.

26. The photochromic article of claim 25, further comprising a hard coat resin layer for scratch resistance.

27. The photochromic article of claim 25, further comprising an anti-reflective coating.

28. The photochromic article of claim 25, further comprising one or more of a hindered amine light stabilizer, an anti-oxidant material, and other stabilizers and additives.

29. The photochromic article of claim 25, wherein the photochromic layer further

comprises a polyurethane host material.

30. The photochromic article of claim 29, wherein the polyurethane host material

comprises PE287.

31. The photochromic article of claim 25, wherein TPP is about 5-100% of the

photochromic dye by weight, and preferably in a range of about 12-60% by weight.

32. The photochromic article of claim 25, wherein the photochromic dye comprises

volcanic grey photochromic dye, or P1499.

33. The photochromic article of claim 32, wherein TPP is about 5-15% of the volcanic grey photochromic dye by weight, and preferably about 12% by weight.

34. The photochromic article of claim 32, wherein TPP is about 30-60% of P1499 by weight, and preferably about 48% by weight.

35. The photochromic article of claim 25, wherein the substrate is a flexible or rigid substrate made of glass or plastic.

36. The photochromic article of claim 35, wherein the substrate has a thickness that is constant or varied at different locations thereof.