| 摘要 |
PURPOSE:To easily obtain a large-sized uniform glass through a solgel process from a metal alkoxide by concentrating the sol solution to a specified extent to suppress formation of bubble holes at the glass bottom. CONSTITUTION:Firstly, a sol solution is prepared by hydrolysis, in the presence of an organic solvent such as methanol and ammonia water, of a metal alkoxide (pref. a Si alkoxide or its partial hydrolyzate). In this case, it is especially preferable that the molar ratio the metal alkoxide/organic solvent/ammonia water be 1 : (3-20) : (2.5-10) and NH3 concentration 0.0005-0.1mol/l; and the temperature is pref. room temperature to the boiling point of the organic solvent. Thence, the sol solution is concentrated to 1.00-1.95 times the metal alkoxide on a volume basis followed by addition of an aqueous solution of catalyst such as hydrofluoric acid and an organic solvent to effect gelation, and the resultant gel is dried and baked, thus obtaining the objective glass.
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