A study of dielectric relaxations in galactose-water mixtures

We studied the frequency dependent dielectric loss spectra of galactose-water mixtures with different water contents in the temperature range which covers the supercooled and glassy states. In the frequency range from 10 mHz to 100 MHz, first we observed the α-relaxation, then slow extra relaxation, and then fast extra relaxation with increasing frequency. The temperature dependent relaxation times of slow and fast extra relaxations were consistent with τJG in the coupling model and that of the γ-relaxation (S. Capaccioli et al., 2006). The relaxation time difference and the relaxation strength of the fast extra relaxations relative to the α-relaxation respectively decreased and increased as the water content increased, indicating that the fast extra relaxation in galactose-water mixtures might be strongly related to the coupling between galactose and water molecules. We also observed crossover phenomena at temperatures close to the glass transition temperatures in the temperature dependent relaxation times of two extra relaxations.