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 evaluate d and compared with those of several kinds of pure silica glasses. The nitr ogen incorporation increased viscosity and Young's modulus. From all result s on both nitrogen-incorporated and pure silica glass, a relationship betwe en Young's modulus and density was deduced, and also a linkage between visc osity and internal friction was derived. The high temperature glass-foaming phenomenon due to nitrogen incorporation was studied. It was found that ho t-isostatic pressing (HIP) treatment is effective for inhibiting foaming. ( C) 2000 Elsevier Science B.V. All-rights reserved.