| 摘要 |
PURPOSE:To contrive to improve refractive index distribution characteristics, by immersing sol obtained from a Si alkoxide in an organic solvent and optionally carrying out pretreatment of soaking a gelatinous porous material in a solution of a water-soluble salt of a metallic ion. CONSTITUTION:First a solution comprising a Si alkoxide as a main component is hydrolyzed to form sol and a gelatinous porous material is obtained from a solution containing a water-soluble salt of a metallic ion. Before the gelatinous porous material is dried and heated to form a glass material, the gelatinous porous material is immersed in an organic solvent which has low solubility of the water-soluble salt and is miscible with water. In the operation, water in the pores is replaced with the organic solvent, the metallic salt is precipitated to promote solidification of the metallic ion. Further optionally pretreatment of soaking the gelatinous porous material in a solution of a water-soluble salt of a different metallic ion is carried out to give a desired refractive index distribution. Promotion of the solidification of the metallic ion improves refractive index distribution characteristics. |
