| 摘要 |
A doped silica-titania glass article is provided that includes a glass article having a glass composition comprising (i) a silica-titania base glass, (ii) a fluorine dopant, and (iii) a second dopant. The fluorine dopant has a concentration of fluorine of up to 5 wt. % and the second dopant comprises one or more oxides selected from the group consisting of Al, Nb, Ta, B, Na, K, Mg, Ca and Li oxides at a total oxide concentration from 50 ppm to 6 wt.%. Further, the glass article has an expansivity slope of less than 0.5 ppb/K2 at 20⃘C. The second dopant can be optional. The composition of the glass article may also contain an OH concentration of less than 100 ppm. |
