High temperature viscosity of nitrogen modified silica glass

Incorporation of nitrogen in silica glass was conducted by sintering porous bodies of silica soot with absorbed NH3 gas. The properties, such as high temperature viscosity, internal friction and Young’s modulus, were evaluated and compared with those of several kinds of pure silica glasses. The nitrogen incorporation increased viscosity and Young’s modulus. From all results on both nitrogen-incorporated and pure silica glass, a relationship between Young’s modulus and density was deduced, and also a linkage between viscosity and internal friction was derived. The high temperature glass-foaming phenomenon due to nitrogen incorporation was studied. It was found that hot-isostatic pressing (HIP) treatment is effective for inhibiting foaming.