Synthesis of a Spiropyran and a Spirooxazine with a Triethoxysilyl Group and their Photochromism in Siloxane Matrices

Abstract

Indoline-spiro-benzopyran and indoline-spiro-naphthoxazine with a 3-(triethoxysilyl)propyl group on N-position of the indoline were synthesized. With or without the aid of a comatrices agent, RSi(OC₂H₅)₃, glass plates were coated with the photochromic compounds by means of the sol-gel method. The glass plates coated with the spiropyran were photochromic. Thermal stability of the colored form increased with increasing bulkiness of RSi(OC₂H₅)₃ used. When triethoxyphenylsilane (R=_C6_H5, ) was used, the thermal stability was improved by a factor of NY compared with that in ethanol. The spirooxazine glass sample produced without the comatrices agent was also photochromic, and the half-life of fading was ca.50 min.