Light-scattering study of the glass transition in silica, with practical implications

The glass transition in silica glass was investigated by light-scattering measurements, and relations between the glass transition temperature, fictive temperature, cooling rate, and viscosity in silica glass were clarified. Furthermore, the effect of OH ions on the structural relaxation was found to work in two ways: The OH ions reduce the activation energy of viscoelastic relaxation, and they also generate a new relaxation due to local structure change. Application of such a relaxational process due to impurities should be effective for controlling the performances of silica glass. (C) 1998 American Institute of Physics.