Melting entropy and its connection to kinetic fragility in glass forming materials

The connections of liquid dynamics to thermodynamics are proven to facilitate understanding the glass transition in liquids. Here, we investigated the melting entropies Delta S-m of various materials with the emphasis on its relation to kinetic fragility. The vibrational entropy Delta Svib-ex in Delta S-m is determined and, a correlation between the ratio of Delta(Svib-ex)/Delta S-m and fragility is shown. The correlation basically reproduces the results determined at glass transition temperatures, T-g, showing the sluggish variation of Delta Svib-ex/Delta S-m from T-g up to the melting point T-m. Delta Svib-ex/Delta S-m is also found to be related to the ionicity for ionic crystals and to T-m for metals. (C) 2016 Elsevier B.V. All rights reserved.