Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Cellular products or processes of preparing a cellular...
Patent
1991-09-24
1993-01-26
Group, Karl
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Cellular products or processes of preparing a cellular...
501 54, 501 55, 65 311, 65 315, 65 31, C03C 400
Patent
active
051822369
ABSTRACT:
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.
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Banash Mark A.
Caldwell J. Brian
Che Tessie M.
Mininni Robert M.
Warden Victor N.
Enichem S.p.A.
Group Karl
Istituto Guido Donegani S.p.A.
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