Gradient index glasses and sol-gel method for their preparation
    1.
    发明授权
    Gradient index glasses and sol-gel method for their preparation 失效
    梯度指数眼镜和溶胶 - 凝胶法制备

    公开(公告)号:US5182236A

    公开(公告)日:1993-01-26

    申请号:US764453

    申请日:1991-09-24

    CPC分类号: C03C1/006

    摘要: A gradient index glass comprised of (SiO.sub.2).sub.m (R.sub.2 O).sub.n X.sub.p, wherein R is Li, Na, K, Rb, or Cs, and X=TiO.sub.2, ZrO.sub.2 and/or HfO.sub.2, m is 44 to 99, n is 0.25 to 20, p is at least 0.1, and m+n+p=100. The gradient index glass is obtained by: (1) mixing a silicon alkoxide and an alcohol in a water solution sufficiently acidic to partially hydrolyze the silicon alkoxide, (2) adding to the mixture a titanium alkoxide or a zirconium alkoxide, (3) causing gelation of the mixture through conversion of the metal alkoxides in solution to an interconnected network of the corresponding metal oxides by stirring or adjusting the pH of the solution, and pouring the solution into a mold, (4) allowing the solution to form a gel, (5) placing the gel in an acid leaching bath to leach out some of the index modifying metal oxide, (6) fixing the gel in a solvent bath, (7) placing the fixed gel in an aqueous or alcoholic alkali salt solution bath to obtain uniform distribution of the alkali ions within the gel, (8) placing the gel in a polar solvent and obtaining an alkali salt precipitate, (9) drying the gel for a time sufficient to remove liquid from the gel, and (10) sintering the dried gel into a transparent gradient index glass.