| 摘要 |
PURPOSE:To produce a large-sized glass with high quality by allowing a gelling temp. of the sol to be a specified low temp. and keeping the temp. until the shrinkage of the wet gel begins to start in the production of glass by the sol-gel method. CONSTITUTION:A liquid sol consisting of the component of the aimed glass is prepared from alkyl silicate and hyper-fine powdery silica as main raw materials and then the glass is produced by the sol-gel method wherein the gel is dried and sintered after gelatinization of the sol. Now the prepared sol is gelatinized at the temp. of <=5 deg.C and the obtained gel is allowed to stand still while slowly returning from the above-mentioned gelatinized temp. to the room temp. at the point when the shrinkage of the wet gel begins to start. In this way, because the sol is gelatinized in low temp., the reaction speed of the dehydration polycondensation is slowed, so the nonuniformity of the reaction in the sol is eliminated. Therefore, large-sized glass of high quality is obtained without any defect in the strength distribution and the bonding of the gel. |
