Constant-volume heat capacity at glass transition

We analyze the jump of heat capacity at glass transition, and calculate the constant-volume heat capacity change Delta C-nu at glass transition in the common glass formers. The experimental heat capacity jump Delta C-p includes both dynamic and dilation's contributions. The Delta C-nu removes the dilation's contribution, and only refers to the dynamic contribution. We find that the ratio Delta C-nu/Delta C-p does not change with the liquid fragility, and almost keeps a constant: 0.85. The results might have implications for a fundamental understanding to the nature of glass transition. (C) 2013 Elsevier B.V. All rights reserved.