Process for producing flakes of glass

A process for producing amorphous or crystalline flakes absorbing ultraviolet radiation, comprising,

• preparing an organic silicon compound, an alcohol for solving the organic silicon compound, a compound effective in imparting capability to absorb ultraviolet radiation, said compound being soluble to the alcohol in which the organic silicon compound is solved and containing a material selected from the group consisting of iron, cerium, titanium, vanadium, chromium, uranium, lead and zinc, and water for hydrolysis of the organic silicon compound,
• mixing the organic silicon compound, alcohol, compound for absorption of ultraviolet radiation and water together so that hydrolysis of the organic silicon compound occurs and polymers containing said material for absorption of ultraviolet radiation grow to thereby form a solution,
• applying the solution onto a substrate,
• drying the solution on the substrate to form a film containing the material for absorption of ultraviolet radiation and silicon, said film, while drying, shrinking and cracking on the substrate to thereby form flakes, and
• heat-treating the flakes to form the amorphous or crystalline flakes, 0.1-70 wt % of an oxide with said material for absorption of ultraviolet radiation being included in the flakes.