Ultraslow dielectric relaxation process in supercooled polyhydric alcohols.

Complex permittivity was obtained on glycerol, xylitol, sorbitol and sorbitol-xylitol mixtures in the supercooled liquid state in the frequency range between 10 microHz and 500 MHz at temperatures near and above the glass transition temperature. For all the materials, a dielectric relaxation process was observed in addition to the well-known structural alpha and Johari-Goldstein beta relaxation process [G. P.

Dielectric studies deny existence of ultraviscous fragile water.

The glass transition, a relaxation phenomenon, sets the low temperature limit to the liquid state. Glassy water that forms only under extreme quenching conditions is unstable against crystallization. Opinions differ on whether the glass transition can be observed at all.

Difference and similarity of dielectric relaxation processes among polyols.

Complex permittivity measurements were performed on sorbitol, xylitol, and sorbitol-xylitol mixture in the supercooled liquid state in an extremely wide frequency range from 10 microHz to 500 MHz at temperatures near and above the glass transition temperature. We determined detailed behavior of the relaxation parameters such as relaxation frequency and broadening against temperature not only for the alpha process but also for the beta process above the glass transition temperature, to the best of our knowledge, for the first time. Since supercooled liquids are in the quasi-equilibrium state, the behavior of all the relaxation parameters for the beta process can be compared among the polyols as well as those for the alpha process.