Abstract: A naphthopyran compound of general formula (I) ##STR1## wherein R.sub.1 represents an alkyl group or an aryl group; each of R.sub.4 and R.sub.5, which may be the same or different, independently represents an alkyl, alkenyl, carbocyclic or heterocyclic group, or R.sub.4 and R.sub.5 taken together with the carbon atom to which they are attached form a carbocyclic ring or a heterocyclic ring; andR.sub.6 represents a hydrogen atom or a substituent selected from alkyl, alkoxy, aryl, aryloxy, heteroaryl, halogen, amino, substituted amino, azo, imino, amide, carboxylate, ester, cyano, trifluromethyl or nitro, and in addition R.sub.6 may represent a carbocyciic or heterocyclic ring fused to ring A.The naphthopyran compounds of the invention are useful as photochromic materials in lenses, e.g. sunglasses, and photochromic transparencies for cars and aircraft.

Abstract: Photochromic compounds having the following structure II ##STR1## in which R.sup.1 is a group selected from hydrogen, alkyl, alkoxy, amino, aryl or heteroaryl;each R.sup.2 is a group selected from C1 to C10 branched or linear alkyls, carbocylic or heterocyclic, the R.sup.2 groups can be independent or together from part of a carboxylic or heterocyclic ring;R.sup.3 is a group selected from hydrogen, alkyl, alkoxy, alkenyl, alkynyl, imino, azo, amino, carboxy ester, amide, cyano, halogen, trifluoromethyl, nitro, aryl or heteroaryl, R.sup.3 is a fused carbocyclic or heterocyclic moiety;Y is a six membered carbocyclic or heterocyclic ring.X links N as shown to the ring Y to form a fused heterocyclic ring.

Abstract: Photochromic materials which have a structure which includes a spiro-pyrrolidinebenzoxazine structure comprising a pyrrolidine part and a benzoxazine part and the benzoxazine part includes at least one mesomeric electron donating group chosen from amino and alkoxy moieties, the one or more mesomeric electron donating groups being linked to the 6' position via attachment to a conjugated system in which the unsaturated bonds forming the linkage are chosen from --C.dbd.C--, --C.tbd.C--, --C.dbd.N-- and --N.dbd.N--.

Abstract: A photo reactive material, such as a photochromic material, which has the following structure: ##STR1## where the variables, A, R, R', R", R*, R.sup.+, m, and n are defined in claim 1.