Method of making colored photochromic glasses
US4290794A · kind A · utility
23Cited by
3References
11Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Nov 19, 1979 |
| Grant date | Sep 22, 1981 |
| Priority date | — |
| Expiry date | Nov 19, 1999 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC03C4/06
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The instant invention is concerned with a method for producing shades of a tint in a photochromic glass, the hue of which will be essentially permanent even after subjecting the glass to temperatures up to about the strain point of the glass. Silver halide crystals constitute the photochromic agents, the glass contains lead, and the method contemplates exposing such a glass to a gaseous reducing atmosphere at temperatures above the strain point of the glass to cause the reduction of silver ions to metallic silver and the reduction of lead ions to metallic lead which coats or alloys with the metallic silver.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.