Influence of heat-treating on microhardness of silica glass КУ-1

The influence of heat-treating on the microhardness of the silica glass KУ-1 is investigated. It is found out that the heat-treatment at 1100$^\circ$ C increase in microhardness and the uniformity improves. This fact is explained by the change of the phase composition of the surface, namely by the appearance of reflexes, related to the phase of cristobalite.