open access

https://hdl.handle.net/2115/9101

Ultraslow dielectric relaxation process in supercooled polyhydric alcohols

英語

2006-04

American Physical Society

Physical review E

73(4)

041510-1-041510-6

Complex permittivity was obtained on glycerol, xylitol, sorbitol and sorbitol-xylitol mixtures in the supercooled liquid state in the frequency range between 10 µ Hz 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 α and Johari-Goldstein β relaxation process [G. P. Johari and M. Goldstein, J. Chem. Phys. 53, 2372 (1970)]. The relaxation time for the new process is always larger than that for the α process. The relaxation time shows non-Arrhenius temperature dependence with correlation to the behavior of the α process and it depends on the molecular size systematically. The dielectric relaxation strength for the new process shows the effect of thermal history and decreases exponentially with time at a constant temperature. It can be considered that a nonequilibrium dynamics causes the new process.

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Copyright © 2006 American Physical Society

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