BROAD-BAND LIGHT-SCATTERING AND DIELECTRIC-DISPERSION OF LIQUID-GLASSTRANSITION IN PROPYLENE-GLYCOL

The liquid-glass transition of propylene glycol was studied using broa dband light scattering spectra obtained using the Sandercook-type Fabr y-Perot interferometer and the additive triple-sating spectrometer. Th e depolarized spectra, in a Liquid phase at 363 K clearly show an alph a peak and a boson peak. With decreasing temperature alpha peak shifts rapidly to a lower frequency but the boson peak does not change signi ficantly. The reduced spectra was analyzed by superposition of the Dav idson-Cole alpha relaxation, a Debye fast relaxation and a boson peak. It is found that the fast relaxation frequency does not depend on tem perature, and its intensity decreases remarkably on cooling towards 13 9 K. The temperature variation of the alpha relaxation was also measur ed using broadband dielectric measurements.