| 摘要 |
PURPOSE:To obtain a high-silica optical glass, by hydrolyzing a solution of a metal alkoxide composed mainly of Si, immersing the resultant gel in an alkaline solution, and drying and sintering the gel. CONSTITUTION:A solution of Si(OR)4 (R is alkyl), or a solution obtained by adding an alkoxide of a doping element for adjusting the refractive index of a transparent quartz glass to the above Si(OR)4 solution, is hydrolyzed in a vessel having a desired shape by adding CH3OH and if necessary HCl to the solution to obtain a gel. The gel is taken out of the vessel, immersed in a mixture of an alcohol and an aqueous solution containing NH4OH, KOH or NaOH at a concentration of 10<-4>-1 deg.mol/l for a sufficiently long time. The gel is picked up from the mixture, and dried by slowly evaporating the water and the alcohol to obtain a dried gel having low bulk density, high porosity and high sintering property. The dried gel is sintered to obtain the objective glass. |
