| 摘要 |
PURPOSE:To obtain a photosensitive compsn. which is colored and becomes cloudy by the exposure to light by constituting the compsn. of polyphosphowolframic acid or a salt thereof, and a homopolymer of polyethylene glycol methacrylate or a copolymer contg. a specified amt. of said homopolymer. CONSTITUTION:Polyphosphowolframic acid or a salt thereof, e.g. Li polyphosphowolframate is used in order to impart photochromic property and clouding property to a photosensitive compsn. A homopolymer of polyethylene glycol methacrylate or a copolymer contg. >=90mol.% polyethylene glycol methacrylate is incorporated into said photosensitive compsn. Also, a monomer copolymerizable with said copolymer, such as methyl methacrylate, etc. is used. The compsn. is colored by the exposure to light and clouded. When it is shielded from the exposure to light, the color is extinguished and the compsn. becomes transparent. |
