PHOTOCHROMIC COMPOUND AND PHOTOFUNCTIONAL ELEMENT USING THE SAME

PROBLEM TO BE SOLVED: To obtain a new photochromic compound capable of forming by itself amorphous thin film which is excellent in repeated durability and great in both absorbance and refractive index changes between points before and after light irradiation, therefore affording excellent photorecording elements. SOLUTION: This new photochromic compound is represented by formula (R1 and R2 are each H or an alkyl; RA is an aromatic ring or a heterocyclic ring; X is O, S or N; ring A is an aliphatic ring, an acid anhydride or maleimide; (n) is an integer of 1-3) or formula II, e.g. a compound of formula III. This new compound is obtained, for example, by the following steps: 2,4- dimethylthiophene as starting material is reacted with zinc chloride followed by 4-iodo-tetraphenylmethane in the presence of (triphenylphosphine) palladium to form 2,4-dimethyl-5-[4-(triphenylmethyl)phenyl]thiophene, and then to which iodine and an aqueous iodic acid solution are added to substitute the heterocyclic ring's 3-position with iodine atom followed by reacting the resultant product with perfluorocyclopentene to be represented as the ring A in formulae I and II.