Photochromic compound, composition and use thereof

Abstract

Disclosed is a compound represented by the following general formula(I): ##STR1## wherein R.sub.1 and R.sub.2, which may be the same or different, represent a hydrogen atom, an alkyl group, an aryl group, an aralkyl group or a substituted amino group, R.sub.3 and R.sub.4, which may be the same or different, represent an alkyl group, or R.sub.3 and R.sub.4 together form a nobornylidene group or bicyclo (3, 3, 1) 9-nonylidene group which may have a substituent, and ##STR2## represents a divalent aromatic hydrocarbon group or divalent unsaturated heterocyclic group which may have a substituent, with the proviso that when R.sub.3 and R.sub.4 represent an alkyl group, ##STR3## represents a bicyclic aromatic fused ring which is substituted with at least one substituent selected form the group consisting of a halgoen atom, an alkyl group, an alkoxy group, --R.sub.5 --S--R.sub.6 and ##STR4## (in which R.sub.5 represents an alkylene group or --O--R.sub.8).sub.n (in which R.sub.8 represents an alkylene group and n is a positive integer), R.sub.6 and R.sub.7, which may be the same or different, represent an alkyl group, and X represents --N<, --P<, ##STR5## at least one of the substituents being an alkyl group having 6 to 20 carbon atoms, an alkoxy group having 6 to 20 carbon atoms, --R.sub.5 --S--R.sub.6 or ##STR6## a composition comprising this compound, and a photochromic lens composed of this composition.