Abstract
Bubbles are essential in the formation of opaque silica glass, because opacity results from light scattering by bubbles dispersed throughout the glass matrix. In this sintering study of slip casting of a silica compact, the formation of bubbles was observed. In the final densification stage, a large number of small bubbles formed at around 1600°C. With increasing sintering temperature, isolated bubbles became larger and, concurrently, the number of bubbles decreased. Opacity increased with increasing sintering temperature up to 1800°C. These results are discussed from the viewpoint of the critical bubble size which determines whether bubbles expand or shrink.
