BRILLOUIN SPECTRA AND STRUCTURAL RELAXATION IN ZNCL2-KCL BINARY MELTS

The Brillouin scattering experiment has been carried out for molten Zn Cl2-KCl binary melts over the composition range 0-45 mol% KCl. The com plete profiles of Rayleigh-Brillouin spectra were obtained at scatteri ng angle of 90-degrees, and at temperatures ranging from 550 to 1000 K by the use of carefully purified samples. Marked change in the shape of the spectrum with variations in temperature and composition has bee n observed and has been concluded to be due to structural relaxation i n the melts. A dispersion of sound wave propagation was observed in th e melts in the hypersonic region. The spectra have been analyzed based on the viscoelastic theory on the assumption of single relaxation. Th e sound velocities at the limiting low and high frequencies and the re laxation time have been determined.