Reduced striae low expansion glass and elements, and a method for making same

The invention is directed to a low expansion glass with reduced striae, the glass have a point-to-point variation in titania content is 0.1 wt % or less through its thickness and a CTE of 0±3 ppb/° C. throughout the temperature range 5-35° C. The invention is further directed to a method for producing the low expansion glass by using a method in which the time for repetition of the oscillation patterns used in the process are 10 minutes or less. In addition, the low expansion glass of the invention can have striae further reduced by heat-treating the glass at temperatures above 1600° C. for a time in the range of 48-160 hours. The invention is also directed to optical elements suitable for extreme ultraviolet lithography, which elements are made of a titania-containing silica glass having a titania content in the range of 5-10 wt. %, a polished and shaped surface have a peak-to-valley roughness of less than 10 nm, an average variation in titania content of less than ±0.1 wt. % as measured through the vertical thickness of the glass and a coefficient of thermal expansion of 0±3 ppb/° C. throughout the temperature range 5-35° C.