Thermodynamics Research Today is a free monthly online journal that collates and summarizes the latest research about Thermodynamics, including details on enthalpy, entropy, energy transitions.

Correlation between thermodynamic and kinetic fragilities in nonpolymeric glass-forming liquids.

Senkov ON, Miracle DB

Air Force Research Laboratory, Materials and Manufacturing Directorate, 2230 Tenth Street, Wright-Patterson AFB, Ohio 45433-7817, USA. oleg.senkov@wpafb.af.mil

A phenomenological relationship between reduced excess heat capacity of supercooled liquid DeltaC(p)(exc)(T(g))DeltaS(m) at the glass transition temperature T(g), fragility index m, and reduced glass transition temperature T(rg)=T(g)T(m), where T(m) is the melting (liquidus) temperature, was derived for fragile nonpolymeric glass-forming liquids under the assumptions that the fragile behavior of these liquids is described by the Vogel-Fulcher-Tammann (VFT) equation; the excess heat capacity of liquid is inversely proportional to the absolute temperature and the VFT temperature T(0) is equal to the Kauzmann temperature T(K). It was found that DeltaC(p)(exc)(T(g))DeltaS(m) is a composite function of m and T(rg), which indicates that the empirical correlation DeltaC(p)(exc)(T(g))DeltaS(m)=0.025m recently identified by Wang et al. [J. Chem Phys. 125, 074505 (2006)] is probably valid only for liquids which have nearly the same values of T(rg).

Published 1 April 2008 in J Chem Phys, 128(12): 124508.
Full-text of this article is available online (may require subscription).

© 2005-2008 Thermodynamics Research Today. All Rights Reserved.