Investigation of the origin of the Rayleigh scattering in SiO2 glass

To investigate the factors determining the Rayleigh scattering in silica glass, the polarized and depolarized light scattering intensities were measured in liquid, supercooled liquid and glassy states of silica. On the heating and cooling processes between glass and liquid, the behavior of the polarized scattering intensity against temperature changed at the temperature corresponding to the melting point of crystobalite. The isothermal compressibility and the depolarization ratio are almost constant in the supercooled liquid state. These results strongly suggest the existence of microcrystalline regions in supercooled liquid and glassy states of silica. The existence of microcrystallites is an important factor in silica glass properties and determines the Rayleigh scattering intensity. (C) 1997 Elsevier Science B.V.