Conventional theories of glass transition are focussed on reproducing the thermodynamic and dynamic properties of the structural a-process. However, in the last decade a class of secondary relaxations, called the JohariGoldstein (JG) b-relaxations, has attracted attention in view of the existence of various correlations and similarities of its properties with the structural a-process. These experimental evidences suggest that the secondary process may play a fundamental role in glass transition, and any theory of glass transition would be incomplete until the inter-relations between the JG b-relaxation and the structural relaxation have been considered. In this paper, some significant experimental results showing several general and nontrivial connections between structural relaxation and JG b-relaxation are reported. In particular, these connections indicate that, like the structural relaxation, the JG b-relaxation is entropy and volume dependent. The experimental facts are consistent with the results of the coupling model.
Does the entropy and volume dependence of the structural alpha-relaxation originate from the Johari Goldstein beta-relaxation?
Prevosto D;
2009
Abstract
Conventional theories of glass transition are focussed on reproducing the thermodynamic and dynamic properties of the structural a-process. However, in the last decade a class of secondary relaxations, called the JohariGoldstein (JG) b-relaxations, has attracted attention in view of the existence of various correlations and similarities of its properties with the structural a-process. These experimental evidences suggest that the secondary process may play a fundamental role in glass transition, and any theory of glass transition would be incomplete until the inter-relations between the JG b-relaxation and the structural relaxation have been considered. In this paper, some significant experimental results showing several general and nontrivial connections between structural relaxation and JG b-relaxation are reported. In particular, these connections indicate that, like the structural relaxation, the JG b-relaxation is entropy and volume dependent. The experimental facts are consistent with the results of the coupling model.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
