Abstract: The invention relates to a group of novel electrochromic compounds. More specifically, it relates to benzazoles and condensed azole compounds substituted with one or several pyridinium rings and the use of these compounds as a variable transmittance medium for the manufacture of an optical article, such as an ophthalmic lens.

Abstract: The photochromic compound is represented by the following general formula (1): wherein, X denotes an oxygen atom or a nitrogen atom unsubstituted or substituted by a substituent selected from the following Y1 group: Y1 group: —R1, -A1(B1)l(A2)m(B2)nR2, -A3A4, -A5R3 R1 denotes a cyano group or the like, R2 denotes an alkyl group or the like, R3 denotes a halogen atom or the like, A1, A2, A3, and A5 each independently denote an alkylene group or the like, A4 denotes a naphthyl group which may be substituted, B1 and B2 each independently denote any one of the divalent groups selected from the following group: l, m, and n are each independently 0 or 1, provided that n is 0 if m is 0, Y2 denotes a hydrogen atom or the like, R denotes a hydrogen atom or the like, denotes a norbornylidene group or the like.

Abstract: A naphthopyran compound of general formula (I) ##STR1## wherein R.sub.1 represents a group of the formula --NR.sub.2 R.sub.3 wherein each of R.sub.2 and R.sub.3, which may be the same or different, independently represents an alkyl group, or a carbocyclic or heterocyclic group, or R.sub.2 and R.sub.3 taken together with the nitrogen atom to which they are attached represent a heterocyclic ring having one or more hetero atoms and which may optionally carry at least one substituent selected from alkyl, aryl, or heteroaryl groups; 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 carboxylcyclic ring or a heterocyclic ring; and R.sub.6 represents a hydrogen atom or a substituent selected from alkyl, alkoxy, aryl, aryloxy, heteroaryl, halogen, a group of formula R.sub.

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: 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.