Effect Of Dynamical Heterogeneity On Heat Capacity At Glass Transition In Typical Silicate Glasses

The heat capacity jump Delta C-p at glass transition and the dynamical heterogeneity are two of the most important features of glass forming liquids. In order to reveal the intrinsic relationship between the two properties, a model glass system (Na2O)(x)(SiO2)(1-x) (x = 0.2-0.35) was studied by the systematic measurements of the Delta C-p and the mechanical relaxation in the supercooled liquid region. A linear increase in Delta C-p with increasing content of Na2O was found, indicating direct contributions of the locally fast dynamics around Na2O to Delta C-p. This positive correlation between the locally heterogeneous dynamics and Delta C-p was further confirmed by the dynamical heterogeneity analyses. Our results might be helpful for understanding the nature of glass transition. (C) 2015 AIP Publishing LLC.