Rewritable photochromic optical disk

摘要

A rewritable photochromic optical disk comprises a photochromic recording layer made of a dibenzothienyl ethene derivative, 1,2-di(2-cyano-3-benzothienyl)-1,2-dicyanoethene capable of assuming first and second states, the first state with a first absorption band transforming into the second state with a second absorption band by irradiating a first light beam of a first wavelength, and the second state transforming into the first state by irradiating a second light beam of a second wavelength in the second absorption band. This rewritable photochromic optical disk has a stability in the repeated recording and erasing information and a high thermal stability and capable of storage of information extended over a long period of time, in accordance with its higher quantum yield than that of the conventional dibenzothienyl ethene derivative so that the achromatic reaction takes place by irradiation of a low power laser beam.