Ultrasonic and hypersonic properties of molten KNO3–Ca(NO3)2 mixture

A picosecond time-domain light scattering technique is used to study the viscoelastic KNO3–Ca(NO3)2 60:40 glass-forming liquid mixture. By using scattering angles between 1.92° and 85.67°, acoustic frequencies from 50 MHz to 4 GHz are sampled. Together with existing ultrasonic and Brillouin scattering data, a temperature-dependent distribution of relaxation times is found to be well fit with a Cole–Cole distribution whose width changes from several decades in the glassy state to nearly single relaxation time in the high-temperature liquid state. The characteristic relaxation time is found to obey the Vogel–Tammann–Fulcher law with T0=338 K.