Testing mode-coupling predictions for and relaxation in Ca0.4K0.6(NO3)1.4 near the liquid-glass transition by light scattering

Light-scattering studies of the liquid-glass transition of Ca0.4K0.6(NO3)1.4 have been carried out from 305 to 23°C. Composite spectra covering over four decades in frequency were obtained by combining data obtained with a Sandercock tandem Fabry-Pérot interferometer and Raman spectra. Two-step relaxation processes were observed in the supercooled liquid near the glass transition. The relaxation exhibits a temperature-independent stretching for T>Tc with Tc 105°C, which is about 45°C above the glass transition temperature. The -relaxation frequency scale indicates critical slowing down when the temperature approaches Tc from either above or below. Scaling analyses for both and relaxations provide good agreement with the predictions of mode-coupling theory.