Nearly constant dielectric loss of polyhydric alcohols

High-frequency broadband dielectric spectroscopy on sugar alcohols below Tg

“…Fig. 3(a) and (b) show the temperature dependence of dielectric loss for sorbitol and xylitol at several frequency points, together with the data reported by Kubo et al [10]. The JG-b relaxation shows up only as a shoulder in the temperature profile, while it exhibits apparent peak in the frequency domain.…”

“…In the previous work [10], we have considered that the loss against temperature can be divided into the two regions. One is corresponding to the effect of the JG-b process and the other one is due to the NCL.…”

“…For type B glass formers, it may be hidden by large contribution from the JG-b process. Kubo et al reported that type B glass formers may also show such behavior in low temperature region below T g [10]. However, this proposition has large ambiguity arising from the contribution of JG-b process.…”

“…There are several earlier works which have reported the behavior of the NCL. However, these investigations have always used the dielectric loss measurements only at lower frequencies below 1 MHz [8,10,11]. Since time-temperature superposition doesn't work for the glassy dynamics, an extrapolation of the experimental results at a low temperature into the values at a high temperature may cause of misunderstanding in the nature of the NCL.…”

Johari-Goldstein Relaxation Far Below Tg : Experimental Evidence for the Gardner Transition in Structural Glasses?

“…Compared to the numerous investigations around and above T g of such glass formers, measurements down to temperatures far below T g are relatively rarely done. Nevertheless, it is clear that in the temperature dependence of quantities as the specific heat, volume, or the dielectric permittivity, so far no obvious anomalies were reported that would point to a phase transition below T g [38,39,40,41] (see also Fig. S1 of the Supplemental Material).…”