Light Scattering from Diffusion-Controlled Phase Separations in Glass

Light-scattering measurements were made on a number of phase-separated glasses in which the number and size of the particles of the new phase were varied. Plots of scattering intensities versus scattering angles showed two unique features: (1) higher scattering intensities were found in the back angles and (2) in some cases sharp maxima in intensities were found. In the first case the experimental data were in excellent quantitative agreement with Goldstein's theory for scattering from systems in which the growth of the new phase is diffusion controlled. In the second case the data were explained using Rayleigh-Gans theory of light scattering for spheres and Frank's theory for diffusion-controlled growth. The results confirmed the existence as well as the extent of the composition gradient around the growing particles as predicted by diffusion-controlled growth theory.