摘要 |
The invention is directed to a method for reducing striae in ultra-low expansion glass, for example, silica-titania glass, by heat-treating the glass at temperatures above 1600° C. for a time in the range of 72-288 hours. The silica-titania glass is formed by substantially simultaneously forming, collecting and consolidating a silica-titania soot formed in one or a plurality of burners using silicon-containing feedstock and a titanium-containing feedstock. In one embodiment of the invention the glass is heat treated without forcing the glass to flow or “move”. The invention was found to reduce the magnitude of striae in an ultra-low expansion glass by at least 50%, and particularly reduces most of the “higher frequency” striae.
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