Photo reactive material

Abstract: A photo reactive material, such as a photochromic material, which has the following structure: where A is a six membered carbocyclic or heterocyclic ring; each R is alkyl, alkenyl, alkynyl, aryl, carbocyclic, heterocyclic, alkyl carbocyclic or alkyl heterocyclic or at least two of the R groups together form part of a carbocyclic or heterocyclic ring or one of the R groups is hydrogen with the other two being selected from the above; R* are independent of one another and are selected from branched or linear C₁-C₁₀ alkyls and carbocyclic or heterocyclic groups or both form part of a carbocyclic or heterocyclic ring; R⁺ m is selected from alkyl alkoxy, amino, halogen, cyano, nitro, trifluoromethyl or aryl and m has a value between 0 and 4; R⁺ n is selected from carbocyclic and heterocyclic groups which are fused to A and n has a value between 0 and 2. R' is selected from hydrogen, alkyl, alkoxy, amino, carbocylic or heterocyclic. R'' is selected from hydrogen, alkyl, aryl, heteroaryl, alkenyl, alkynyl, alkoxy, aryloxy, amino, halogen, cyano, nitro, trifluoromethyl, imino, azo, carboxy ester or amide or is a carbocyclic or heterocyclic group fused to the moiety.

Description: The present invention relates to a photo reactive material, commonly known as a photo chromic material, and, in particular, to photo reactive materials which can be used when dispersed in a polymeric material, for example, polyurethane. For a long period of time photo reactive materials have been known. In the early years these materials were limited in their use to situations where they were dispersed in glass media, for example GB 1515641 discloses photochromic materials for use in boro-silicate glass and GB 1515642 discloses photochromic materials for use in alumino phosphate glass. In recent years with the movement of related industries to the replacement of the expensive glasses with polymeric materials there has been a lot of work in developing photo reactive materials that work in polymeric environments. To a degree the following two patents/patent applications of this applicant have solved the problem and provided a suitable solution; EP-A-0 245 020 and EP-A-0 294 056. These patent applications respectively relate to a suitable spiro-oxazine structure of material for use as a photo reactive material, and a polymeric system for locking the photo reactive material into a structure. The development of photo chromic/photo reactive materials which can be used in polymeric systems has been moving forward at a fairly rapid rate, and consequently some problems have been encountered. One of these is that most suitably coloured systems will actually incorporate a mixture of differing materials which have differing colours of activation. Unfortunately, also most of these materials have different recovery times to the uncoloured state. Therefore, as the activated system recovers it undergoes an apparent colour change. In some circumstances this can lead to a garish unacceptable colour. Broadly speaking the whole of this problem revolves around the kinetics of the materials involved in the system. The present invention is concerned with providing a solution to the above mentioned problem by finding a means by which the kinetic behaviour of a material can be controlled or adapted. In accordance with the present invention a photochromic compound has the following structure: where A is a six membered carbocyclic or heterocyclic ring; each R is alkyl, alkenyl, alkynyl, aryl, carbocyclic, heterocyclic, alkyl carbocyclic or alkyl heterocyclic, or at least two of the R groups together form part of a carbocyclic or heterocyclic ring or one of the R groups is hydrogen with the other two being selected from above; R* are independent of one another and are selected from branched or linear C 1 -C 10 alkyls and carbocyclic or heterocyclic groups or both form part of a carbocyclic or heterocyclic ring; R + m is selected from alkyl, alkoxy, amino, halogen, cyano, nitro, trifluoromethyl or aryl and m has a value between 0 and 4; R + n is selected from carbocyclic and heterocyclic groups which are fused to A and n has a value between 0 and 2. R' is selected from hydrogen, alkyl, alkoxy, amino, carbocylic or heterocyclic. R" is selected from hydrogen, alkyl, aryl, heteroaryl, alkenyl, alkynyl, alkoxy, aryloxy, amino, halogen, cyano, nitro, trifluoromethyl, imino, azo, carboxy ester, amide or is a carbocyclic or heterocyclic group fused to the moiety. In a second form the present invention comprises a photochromic compound which has the following structure: where R are independent of one another and are selected from the following: alkyl, alkenyl, alkynyl, carbocyclic heterocyclic, alkylcarbocyclic or alkylheterocyclic or at least two of the R groups together form part of a carbocyclic ring or one of the R group is hydrogen with the other 2 being selected from the above listing; R* are independent of one another and are selected from branched or linear C 1 -C 10 alkyl or carbocyclic or heterocyclic or both form part of an alicyclic ring; R + m is selected from hydrogen, aryl, alkyl, alkoxy, amino, halogen, cyano or nitro and m has a value between 0 and 4; R + n is selected from alicyclic, heterocyclic, aryl or heteroaryl groups and n has a value between 0 and 2; R + are independent and are selected from hydrogen, alkyl, aryl, heteroaryl, alkenyl, alkynyl, alkoxy, aryloxy, amino, halogen, cyano, nitro, trifluromethyl, imino, azo, carboxy ester, amide, or both form part of a carbocyclic or heterocyclic ring; R° is selected from hydrogen, alkyl, alkoxy, acyl, phenyl, an halogen, cyano group, nitro group, an amine group, or trifluro methyl or former part of a alicyclic, acyl or hetero aryl group;. and X is nitrogen or a -CH - group contained in a carbocyclic ring or heterocyclic ring. In the present invention the presence of the tertiary/quarternary alkylmethylene (-N-CH 2 -CR 3 ) grouping close to the photoactive centre of the molecule affects the rate at which the photoactive material recovers. Further by controlling the groups attached to the tetrahedral -CR 3 part of this grouping the kinetics of the molecule recovery can be further adjusted and controlled. In essence the kinetics of the photo reactive material can be adjusted and controlled, and the grouping in question has little or no effect on the colour of the molecules formed in the activated state. Therefore, the kinetics of the materials used in a system can be suitably adjusted to control the fade back/recovery of the material involved. In essence the placement of the -CH 2 -in the =N-CH 2 -CR 3 grouping between the nitrogen and tetrahedral CR 3 slows up dramatically the kinetics of the recovery from the activated state. Consequently, one distinct advantage which is seen over the currently available materials is due to the slower relative recovery rate. As a result of the slower recovery rate the activated material stays in the coloured state longer. Consequently, at any one time more of the photo reactive material will be in the activated/coloured state. The net result of this is the article containing the photoreactive material has a higher induced darkness at a particular temperature. In one arrangement of the present invention at least two of the R groups form part of an alicyclic ring which is cyclohexyl, adamantyl or norbornyl in structure. The suitable C 1 -C 10 alkyl for representation as the R* group includes methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, neopentyl and isopentyl. In one particular embodiment of the present invention the R* groups form part of an alicyclic ring which is cyclo hexyl, adamantyl or norbornyl in structure. In one particular arrangement of the present invention the R + and R° groups together can form part of a fused ring which can be carbocyclic or heterocyclic in structure. One of the important factors behind the photo reactive materials is the ability to manufacture the actual materials involved. With the more simple photoreactive materials and only the simple materials the commonly known Quaternisations of Fisher Base Analogue synthesis route can be adopted. However as will be appreciated by those skilled in the art with the more complex photo reactive materials, particularly where branched chain alkyls are involved, the Quaternisations of Fisher Base Analogue route does not provide a viable synthesis route. The photochromic compounds in accordance with the present invention can be synthesised using a route which has been pioneered by the present applicant and is broadly outlined in GB 2190088 with regard to 6' amino compounds. However, in order to assist with the understanding of the synthesis route a broad outline is given below. In the synthesis of these N-(branched)alkyl Fischer Bases the most important step is in the formation of the N-(branched)alkyl aniline derivative (1). A general synthetic route for the anilino derivatives is based upon work by A R Katritzky et al Org. Prep. Proceed. Int. Briefs, 1989, 21(3), 340-1; and J. Chem. Soc. Perkins Trans. 1, 1987, 799-804. The transformation required to convert the aniline (1) to the corresponding Fischer base (5) follows well known synthetic methods comprehensively covered by B. Robinson, The Fischer Indole Synthesis, Wiley-Interscience, 1982. The general method employed for the synthesis of spiroindolinooxazines photochromics involves the condensation of an alkylidene indoline heterocycle (Fischer Base analogues) with a ortho-nitroso aryl alcohol as described in Applied Photochromic Polymer Systems, Blackie, Ed.C. B. McArdle, 1992, Chapter 2. The photo reactive materials described above, when in use, are locked or encapsulated in a polymeric host material. It is preferred that the host material does not affect, for example, degrade or destroy the photo reactive material. However, most of the materials can operate effectively when this does not occur to a substantial degree. Examples of suitable polymers for host materials are optically clear materials, for example, polymers of polyol(allyl carbonate)-monomers, polyacrylates, such as polymethylmethacrylates, cellulose acetate, cellulose triacetate, cellulose acetate propionate, cellulose acetate butyrate, poly(vinyl acetate), poly(vinyl alcohol), polyurethanes, polycarbonates, polyethylene terephthalate, polystyrene, poly(styrene methylmethacrylate) coopolymers, poly(styrene acrylonitrile) copolymers, and polyvinylbutyral. Transparent copolymers and blends of the transparent polymers are also suitable as host materials. Preferably, the host material is an optically clear polymerized organic material such as triethylene glycol dimethacrylate (TEGDM) namely diethylene glycol bis(allyl carbonate), one form of which is sold under the trade name CR-39. The invention will now be illustrated by way of example and test data. The tests involved were primarily two fold, and details of these are given below: A) Steady State Induced Optical Density In this test 0.2% w/w concentration of the photo reactive material under test was dispersed in a polyurethane (1 mm thick) plate and illuminated at 20°C by Xenon Arc filtered to Air Mass 2. Once the sample sender test had reached a steady state data was taken. B) Induced Optical Density against Temperature In this test 0.05% w/w concentration of the photo reactive material under test was dispersed in a polyurethane (1 mm thick) plate and illuminated at a particular temperature by Xenon Arc filtered to Air Mass 2. Example 1 1,3-Dihydro-3,3-dimethyl-1-isobutyl-6'-(2,3-dihydroindol-1-yl)spiro[2H-indole-2,3'-3H-naphtho[2,1-b][1,4]oxazine]. A mixture of 4-indolino-1-nitroso-2-naphthol (0.90g; 0.0031 mol) and 1,3-dihydro-3,3-dimethyl-1-isobutyl-2-methyleneindoline (0.66g; 0.0031 mol) in 1,4-dioxan (40.0 ml) was stirred and heated under reflux for 72h. The solution was evaporated and flash-chromatographed over silica (5% ethyl acetate in hexane) to give a brown gum which solidified on triturating with light petroleum (b.p. 30-40) to yield 1,3-Dihydro-3,3-dimethyl-l-isobutyl-6'-(2,3-dihydroindol-1-yl)spiro[2H-indole-2,3'-3H-naphtho[2,1-b][1,4]oxazine] as a yellow solid (0.88 g; 58%). m.p. 167-8°C Example 2 1,3-Dihydro-3,3-dimethyl-1-(2-ethylhex-1-yl)-6'-(2,3-dihydroindol-1-yl)spiro[2H-indole-2,3'-3H-naphtho[2,1-b][1,4]oxazine]. m.p 150-3°C Example 3 1,3-Dihydro-3,3-dimethyl-1-cyclohexylmethyl-6'-(2,3-dihydroindol-1-yl)spiro[2H-indole-2,3'-3H-naphtho[2,1-b][1,4] oxazine]. m.p. 148-50°C Example 4 1,3-Dihydro-3,3-dimethyl-1-(2-phenylprop-1-yl)-6'-(2,3-dihydroindol-1-yl)spiro[2H-indole-2,3'-3H-naphtho[2,1-b][1,4]oxazine]. m.p. 199-201°C Example 5 1,3-Dihydro-3,3-dimethyl-1-neopentyl-6'-(2,3-dihydroindol-1-yl)spiro[2H-indole-2,3-'3H-naphtho[2,1-B][1,4]oxazine m.p.149.5-51°C Comparative Example 1 1,3-Dihydro-1,3,3-trimethyl-6'-(2,3-dihydroindol-1-yl) spiro[2H-indole-2,3'-3H-naphtho[2,1-b][1,4]oxazine]. A mixture of 1-nitroso-2-naphthol (17.3 g; 0.10 mol) and indoline (23.8 g; 0.20 mol) in trichloroethylene (150 ml) was heated under reflux for 10 min. A solution of 1,3-dihydro-1,3,3-trimethyl-2-methyleneindoline (17.3 g; 0.1 mol) in trichloroethylene (100 ml) was added in one batch and the resulting mixture heated under reflux for lh. The solution was evaporated and the oily residue treated with acetone to yield 1,3-Dihydro-1,3,3-trimethyl-6'-(2,3-dihydroindol-1-yl)spiro [2H-indole-2,3'-3H-naphtho[2,1-b][1,4]oxazine] as a yellow solid (4.44 g; 10%). m.p 255-7°C Comparative Example 2 1,3-Dihydro-3,3-dimethyl-1-isopropyl-6'-(2,3-dihydroindol-1-yl)spiro[2H-indole-2,3'-3H-naphtho[2,1-b][1,4]oxazine ]m.p. 175-78°C (decomp.) Comparative Example 3 1,3-Dihydro-3,3-dimethyl-1-isopentyl-6'-(2,3-dihydroindol-1-yl)spiro[2H-indole-2,3'-3H-naphtho[2,1-b][1,4] oxazine] m.p. 116-18°C (decomp) Steady State Induced Optical Density (IOD) Example bleached IVT darkened IVT IOD IVT 1 70.9 1.1 1.79 2 77.7 0.9 1.92 3 76.7 1.1 1.86 4 83.8 0.9 1.99 5 77.6 0.4 2.30 Comparative Examples 1 89.9 6.0 1.18 2 87.8 5.7 1.19 3 80.3 2.1 1.59 IOD Vs. Temperature 14°C 21°C 30°C 38°C Example 1 1.56 1.22 0.94 0.58 2 1.49 1.28 0.97 0.63 4 1.43 1.24 0.95 0.55 5 1.84 1.43 1.37 0.96 Comparative Example 1 1.19 0.85 0.55 0.29 Example 6 1,3-Dihydro-3,3-dimethyl-1-neopentylspiro[2H-indole-2, 3'-3H-naphtho[2,1-b][1,4]oxazine]. A mixture of 1-nitroso-2-naphthol (0.34 g; 0.002 mol) and 1,3-dihydro-3,3-dimethyl-2-methylene-1-neopentylindoline (0.46g; 0.002 mol) in methanol (25.0 ml) was heated under reflux for 4.5 h. The solution was evaporated and the residue flash-chromatographed over silica (5% diethyl ether in hexane) to give a yellow gum which solidifed on trituration with acetone to afford 1,3-Dihydro-3,3-dimethyl -1-neopentylspiro[2H-indole-2,3'-3H-naphtho[2,1-b][1,4]oxaz ine] as a white solid (0.56 g; 73%). m.p. 167-70°C Example 7 1,3-Dihydro-3,3-dimethyl-1-isobutylspiro[2H-indole-2,3 '-3H-naphtho[2,1-b][1,4]oxazine]. m.p. 159-60°C Example 8 1,3-Dihydro-3,3-dimethyl-1-(2-phenylprop-1-yl)spiro[2H -indole-2,3'-3H-naphtho[2,1-b][1,4]oxazine]. m.p. 136-141°C Comparative Example 4 1,3-Dihydro-1,3,3-trimethylspiro[2H-indole-2,3'-3H-nap htho[2,1-b][1,4]oxazine]. A mixture 1,3-dihydro-1,3,3-trimethyl-2-methyleneindoline (3.62 g; 0.021 mol) and 1-nitroso-2-naphthol (3.46 g; 0.02 mol) in ethanol (80.0 ml) was heated under reflux for 2h. The solution was evaporated and the residue flash-chromatographed over silica (dichloromethane) to give 1,3-Dihydro-1,3,3-trimethylspiro[2H-indole-2,3'-3H-naphtho[2,1-b] [1,4]oxazine] as a pale yellow solid (3.96 g; 60%). m.p. 127-30°C Comparative Example 5 1,3-Dihydro-3,3-dimethyl-1-benzylspiro[2H-indole-2,3'-3H-na phtho[2,1-b][1,4]oxazine]. m.p. 202-4°C Comparative Example 6 1,3-Dihydro-3,3-dimethyl-1-octadecylspiro[2H-indole-2, 3'-3H-naphtho[2,1-b][1,4]oxazine]. m.p. 65°C Steady State Induced Optical Density (IOD) Example bleached IVT darkened IVT IOD IVT 6 88.3 21.3 0.77 7 90.2 27.5 0.52 8 89.5 24.2 0.57 Comparative Example 4 88.7 47.9 0.27 5 81.7 48.1 0.23 6 87.9 49.2 0.25 Example 9 1,3-Dihydro-3,3-dimethyl-1-(2-phenylprop-1-yl)-6'-(p-diethylaminophenyl)spiro[2H-indole-2,3'-3H-naphtho[2,1-b][1, 4]oxazine]. A mixture of 4-(p-diethylaminophenyl-1-nitroso-2-hydroxynaphthalene (5.76 g: 0.018 mol) and 1,3-Dihydro-3,3-dimethyl-1-(2-phenylprop-1-yl)-2-methyleneindoline (4.98 g; 0.018 mol) in methanol (175.0 ml) was heated under reflux for 22h. The solution was evaporated and the residue flash-chromatographed over silica (10% diethyl ether in hexane) to give a green gum which solidifed upon treatment with petroleum ether (b.p. 40-60) to yield 1,3-Dihydro-3,3-dimethyl-1-(2-phenylprop-1-yl)-6'-(p-diethy laminophenyl)spiro[2H-indole-2,3'-3H-naphtho[2,1-b][1,4]oxa zine] as a pale green solid (1.08 g; 10%). m.p. 74-80°C. Example 10 1,3-dihydro-3,3-dimethyl-1-neopentyl-6'-(p-diethylamin ophenyl)spiro[2H-indole-2,3'-[3H]naphth[2,1-b][1,4] oxazine]. m.p. 190-3°C Comparative Example 7 1,3-dihydro-1,3,3-trimethyl-6'-(p-diethylaminophenyl)s piro[2H-indole-2,3'-[3H]naphth[2,1-b][1,4]oxazine]. A solution of 4-(p-diethylaminophenyl)-1-nitroso-2-hydroxynaphthalene (0.85 g; 0.0027 mol) and 1,3-dihydro-1,3,3-trimethyl-2-methyleneindoline (0.5 g; 0.0029 mol) in methanol (60 ml) under nitrogen, was heated under reflux for 24 hours. The solution was then evaporated and chromatographed over silica (1 part diethyl ether to 10 parts pet. ether) to afford 1,3-d=hydro-1,3,3-trimethyl-6'-(p-diethylaninophenyl)spiro[2H-indole-2,3'-[3H ]naphth[2,1-b][1,4]oxazine]( 0.47 g; 36%) as a yellow solid. m.p. 157-8°C Steady State Induced Optical Density (IOD) Example bleached IVT darkened IVT IOD IVT 9 87.9 29.1 0.48 10 83.8 8.8 0.98 Comparative Example 7 87.7 48.2 0.26

Claims: A photochromic compound having the following structure: where A is a six membered carbocyclic or heterocyclic ring; each R is alkyl, alkenyl, alkynyl, aryl, carbocyclic, heterocyclic, alkyl carbocyclic or alkyl heterocyclic or at least two of the R groups together form part of a carbocyclic or heterocyclic ring or one of the R groups is hydrogen with the other two being selected from the above; R* are independent of one another and are selected from branched or linear C 1 -C 10 alkyls and carbocyclic or heterocyclic groups or both form part of a carbocyclic or heterocyclic ring; R + m is selected from alkyl alkoxy, amino, halogen, cyano, nitro, trifluoromethyl or aryl and m has a value between 0 and 4; R + n is selected from carbocyclic and heterocyclic groups which are fused to A and n has a value between 0 and 2. R' is selected from hydrogen, alkyl, alkoxy, amino, carbocylic or heterocyclic. R" is selected from hydrogen, alkyl, aryl, heteroaryl, alkenyl, alkynyl, alkoxy, aryloxy, amino, halogen, cyano, nitro, trifluoromethyl, imino, azo, carboxy ester or amide or is a carbocyclic or heterocyclic group fused to the moiety. A photochromic compound which has the following structure: where R are independent of one another and are selected from the following: alkyl, alkenyl, alkynyl, carbocyclic heterocyclic, alkylcarbocyclic or alkylheterocyclic or at least two of groups together form part of a carbocyclic or heterocyclic ring or one of the R groups is hydrogen with the other 2 being selected from the above listing; R* are independent of one another and are selected from branched or linear C 1 -C 10 alkyl or carbocyclic or heterocyclic or both form part of an alicyclic ring; R + m is selected from hydrogen, aryl, alkyl, alkoxy, amino, halogen, cyano or nitro and m has a value between 0 and 4; R + n is selected from carbocyclic, heterocyclic, aryl, heteroaryl groups and n has a value between 0 and 2; R + are independent and are selected from hydrogen, alkyl, aryl, heteroaryl, alkenyl, alkynyl, alkoxy, aryloxy, amino, halogen, cyano, nitro, trifluromethyl, imino, azo, carboxy ester, amide, or both form part of a carbocyclic or heterocyclic ring; R° is selected from hydrogen, alkyl, alkoxy, acyl, phenyl, an halogen, cyano group, nitro group, an amine group, or trifluro methyl or form part of a alicyclic, acyl or hetero aryl group; and X is nitrogen or a - CH - group contained in a carbocyclic ring or heterocyclic ring. A photochromic compound as claimed in claim 1 or claim 2 wherein at least two of the R groups form part of an alicyclic ring which is cyclohexyl, adamantyl or norbornyl in structure. A photochromic compound claimed in any one of the preceding claims, wherein R* group includes methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, neopentyl and isopentyl. A photochromic compound as claimed in any one of claims 1 to 3, wherein the the R* groups form part of an alicyclic ring which is cyclo hexyl, adamantyl or norbornyl in structure. A photochromic compound as claimed in claim 1 or claim 2, wherein the R + and R° groups together can form part of a fused ring which can be carbocyclic or heterocyclic in structure. 1,3-Dihydro-3,3-dimethyl-1-isobutyl-6'-(2,3-dihydroindol-1-yl)spiro[2H-indole-2,3'-3H-naphtho [2,1-b][1,4]oxazine]. 1,3-Dihydro-3,3-dimethyl-1-(2-ethylhex-1-yl)-6'-(2,3-dihydroindol-1-yl)spiro[2H-indole-2,3'-3H-naphtho[2,1-b][1,4]oxazine]. 1,3-Dihydro-3,3-dimethyl-1-cyclohexylmethyl-6'-(2,3-dihydroindol-1-yl)spiro[2H-indole-2,3'-3H-naphtho[2,1-b] [1,4] oxazine]. 1,3-Dihydro-3,3-dimethyl-1-(2-phenylprop-1-yl)-6'-(2,3-dihydroindol-1-yl)spiro[2H-indole-2,3'-3H-naphtho[2,1-b][1,4]oxazine]. 1,3-Dihydro-3,3-dimethyl-1-neopentyl-6'-(2,3-dihydroindol-1-yl)spiro[2H-indole-2,3-'3H-naphtho[2,1-B][1,4]ox azine. 1,3-Dihydro-3,3-dimethyl-1-neopentylspiro[2H-indole-2, 3'-3H-naphtho[2,1-b][1,4]oxazine]. 1,3-Dihydro-3,3-dimethyl-1-isobutylspiro[2H-indole-2,3 -3H-naphtho[2,1-b][1,4]oxazine]. 1,3-Dihydro-3,3-dimethyl-1-(2-phenylprop-1-yl)spiro[2H -indole-2,3'-3H-naphtho[2,1-b][1,4]oxazine]. 1,3-Dihydro-3,3-dimethyl-1-(2-phenylprop-1-yl)-6'-(p-d iethylaminophenyl)spiro[2H-indole-2,3'-3H-naphtho[2,1-b][1,4]oxazine]. 1,3-dihydro-3,3-dimethyl-1-neopentyl-6'-(p-diethylamin ophenyl)spiro[2H-indole-2,3'-[3H]naphth[2,1-b][1,4] oxazine]. A polymeric material comprising a photochromic compound as claimed in claim 1 or 2 locked or encapsulated in a polymeric host material. A polymeric material as claimed in claim 17 wherein the host material is selected from polymers of polyol(allyl carbonate)-monomers, polyacrylates, including polymethylmethacrylates, cellulose acetate, cellulose triacetate, cellulose acetate propionate, cellulose acetate butyrate, poly(vinyl acetate), poly(vinyl alcohol), polyurethanes, polycarbonates, polyethylene terephthalate, polystyrene, poly(styrene methylmethacrylate) coopolymers, poly(styrene acrylonitrile) copolymers polyvinylbutyral or blends thereof. A polymeric material as claimed in claim 17 wherein the host material is an optically clear polymerized organic material and to triethylene glycol dimethacrylate (TEGDM). A polymeric material as claimed in claim 17 wherein the host material is diethylene glycol bis(allyl carbonate).

Inventors: GABBUTT CHRISTOPHER DAVID, HEPWORTH JOHN DAVID, MARSDEN SEAN DEREK, RICKWOOD MARTIN, GABBUTT, CHRISTOPHER DAVID, HEPWORTH, JOHN DAVID, MARSDEN, SEAN DEREK, RICKWOOD, MARTIN
Applicants: PILKINGTON PLC
Application year: 1993
Main classification: G03C1
IPC codes: C09K9, C08L33, C07D498, C08L75, C09K3, C08K5, G03C1, C08L29, C08L67, C08L1, C08L25, C08L69