| 摘要 |
PURPOSE:To form easily an easily sinterable gel having a small bulk density in the process for prepg. glass from an alkoxide as a raw material by the sol-gel method, by substituting a dispersion medium contained in the gel with water, and then drying the gel by freezing. CONSTITUTION:Water is added to an alcoholic soln. of at least one alkoxide of Si, B, Ge, Pb, etc. to cause hydrolysis and gelation. The formed gel is taken out of the dispersion medium and transferred to water, which is heated appropriately to evaporate remaining alcohol. Then, the gel contg. water as dispersion medium is dried by freezing to form dry gel having a small bulk density, and the dry gel is sintered at a temp. below its m.p. to obtain a glass. Since the material is dried in the state of gel by the process described above, higher freeze-drying temp. is applicable than the case of drying a gel contg. alcohol (i.e. a little lower temp. than 0 deg.C). Moreover, the dry gel obtd. by this process is sinterable very easily. |
