Broadband dielectric study of α-β separation for supercooled glycerol-water mixtures

Broadband dielectric measurements for 60, 65, 70, 80, and 100 wt% glycerol-water mixtures were performed in the frequency range of 10 muHz-30 GHz and in the temperature range of 148-298 K. In the lower temperature range, the separation of the beta- and alpha-processes occurred for all the mixtures. The relaxation strength of the alpha-process below the separation temperature exhibits a maximum at a mole fraction of water, x(w) congruent to 0.55, and the relaxation strength of the beta-process increases with increasing x(w). In our previous study, the concentration dependence of the dielectric behavior of the alcohol-water mixtures at 25 degreesC was interpreted using a cooperative domain (CD), in which the re-orientation of molecules occurred cooperatively. The concentration dependence of the dielectric behavior for the glycerol-water mixtures is interpreted using a CD model. (C) 2002 Elsevier Science B.V. All rights reserved.