Boule oscillation patterns for producing fused silica glass

摘要

Oscillation/rotation patterns for improving the off axis homogeneity of fused silica boules are provided. The patterns reduce the optical effects of periodic off-axis striae by decreasing the ratio of DELTA nstriae to DELTA zstriae, where DELTA nstriae is the average peak-to-valley magnitude of the striae and DELTA zstriae is there average peak-to-peak period. The oscillation/rotation patterns have long repeat periods and cause soot-producing burners to trace out substantially spiral-shaped patterns on the surface of the boule.