Relaxation time and cooling rate of a liquid in the glass transition range

Abstract

The transfer of kinetic units (atoms or groups of atoms) in amorphous materials from one quasiequilibrium position to another quasi-equilibrium position is governed by the fluctuations of both the energy and the entropy of the system. In the glass transition range of liquids, the entropy mechanism plays a dominant role: fluctuations of the particle packing appear to be more significant than the accumulation of the energy. At high temperatures above the glass transition range, the energy mechanism plays a decisive role. The physical meaning of the parameter involved in the Bartenev equation relating the relaxation time to the cooling rate at the glass transition temperature is discussed. A technique is proposed for calculating this parameter with allowance made for the temperature dependence of the activation energy in the liquid-glass transition range. A variant of the modification of this equation is considered.

Vitrification in a wide cooling rate range: The relations between cooling rate, relaxation time, transition width, and fragility

“…1, 13,14,16,17 The relation between β c and τ r is usually described by the Frenkel-Kobeko-Reiner (FKR) relation 3, [17][18][19] |β c |τ r (T g ) = C,…”

Spherulitic crystallization of quartz-like GeO2 and correlated second harmonic generation in sodium tantalum germanate glasses

“…Colorless and homogeneous glass samples of composition 70GeO2-10Na2O-20Ta2O5 were obtained by meltquenching as presented in Table 1. DSC measurements give important informations about glass stability and structural changes in the material such as crystallization mechanisms, among others [39], [40]. The DSC curve of our glass sample presented in Fig.…”

Pre-Crystallization Criteria and Triple Crystallization Kinetic Parameters of Amorphous–Crystalline Phase Transition of As40S45Se15 Alloy

“…The g A and g B constants equal to (333.35± 0.046 K) and (6.18 ± 0.016 min), respectively. One can obtain that values of the glass transition temperature, for the investigated glassy system increase with increasing g T heating rate,  as a result of the system doesn't get abundant time for full nucleation and growth [32,33]. On the other hand, the heating rate linked to the relaxation time ( g  ) for glass transition of atoms via the following equation [33]: 1.…”