| 摘要 |
PURPOSE:To improve durability for repetition of coloration and fade-out of color by forming a protective layer for shielding ultraviolet rays comprising a photochromic compd. CONSTITUTION:A recording film 2 comprising a photochromic compd. (e.g. a fulgide expressed by the formula I), and a polymer binder and a protective film 3 for shielding ultraviolet rays comprising polymethyl methacrylate, etc., are formed successively on a substrate 1 comprising quartz glass, etc. The optical medium is colored by the irradiation with ultraviolet rays, and faded out color by the irradiation with visible rays, but the durability for repetition of coloration and fade-out of color is improved by providing the film 3. In the formula, each X and Y is O, N, etc.; each R1-R6 is H, alkyl, etc. |
