Preparation of silane-WO3 film through sol–gel method and characterization of photochromism

The sol of silane and WO3 was prepared from tetraethyl orthosilicate (TEOS) and methacryloxy-propyl-trimethoxy silane (KH570) with a novel route as described in previous work, and the aqueous WO3 solution was prepared from ammonium tungstate. These two sols were mixed by stirring for about 1 hour with a certain ratio. Through sol–gel method, the transparent hybrids coating of organic silane and tungsten oxide was prepared by spraying or dipping on the glass substrates, and then were heat-treated at a certain temperature. The photochromic properties were investigated. AFM was used to investigate the surface structure of the prepared coatings. The crystalline phase was studied through X-ray diffraction. UV lights with different wavelengths were used to get the coloration of the film. The results show that silane-WO3 film exhibits better photo-chromic properties under UV light irradiation.