Fragility of metallic glass-forming liquids: A simple thermodynamic connection

We will demonstrate that kinetic fragility of a glass-forming liquid is quantitatively related to Delta S-f(T-m-T-K), where Delta S-f is the entropy of fusion, T-m the melting point, and T-K the Kauzmann temperature of a glass-forming liquid. A positive correlation between Delta Sf (T-m - T-K) and the kinetic fragility was found to hold in metallic glass-forming liquids, where both thermodynamic and kinetic data are available. It will be demonstrated that such correlation is consistent with the energy landscape model of the glass transition. Furthermore, the thermodynamic fragility index Delta S-f(T-m-T-K) was reduced to Delta S-f/T-m assuming T-K approximate to T-m/2, and the correlation between Delta S-f/ T-m and kinetic fragility was discussed within the context of recently proposed cluster model of the glass transition. (c) 2005 Elsevier B.V. All rights reserved.