Photochromic compounds

Abstract

A photochromic compound has the formula (I) wherein R,is selected from the group including substituted amino aryl moieties, substituted cyclic amino aryl moieties and substituted N-indolinoaryl or N-tetrahydroquinolino aryl groups, R,is selected from the group including linear or branched C,-C,alkyl, linear or branched C,-C,alkenyl or polyalkenyl, C,-C,alkynyl or polyalkynyl, aryl, heteroaryl, linear or branched C,-C,alkyl aryl, linear or branched C,-C,alkyl-cycloalkyl or -bicycloalkyl or -tricycloalkyl or substituted -cycloalkyl or -bicycloalkyl or -tricycloalkyl, linear or branched C,-C,haloalkyl or perhaloalkyl, linear or branched C,-C,alkoxyalkyl or peralkoxyalkyl, linear or branched C,-C,alkylthioalkyl or peralkylthioalkyl, linear or branched C,-C,amino alkyl or peraminoalkyl, C,-C,cycloalkyl or substituted cycloalkyl, C,-C,bicycloalkyl or substituted bicycloalkyl, C,-C,tricycloalkyl or substituted tricycloalkl or linear or branched C,-C,hydroxyalkyl or perhydroxyalkyl; R,and R,which may be the same or different are R,or R,and R,are conjoined to form a spiro linked C,-C,cyclic system or substituted cyclic system; and wherein R,and R,are each selected from R,or hydrogen, halogen, nitro, nitroso, amino, acetamido, C,-C,N-alkylamido, alkoxycarbonyl, nitrile, carboxy, hydroxy, aryloxy, C,-C,alkoxy, a heteroatom which is O or N or S or P which in turn can be bonded either singly or multiply to carbon, oxygen, sulphur or nitrogen, C,-C,alkoxy or alkylthio or aryl or aryloxy or multiples thereof.