Thermodynamic fragility and kinetic fragility in supercooling liquids: A missing link in molecular liquids

Ito, Moynihan, and Angell [Nature 398, 492 (1999)] compared the kinetic and thermodynamic measures of a glassformer’s “fragility.” For the liquids they considered which include molecular, covalent, and ionic substances, thermodynamic fragility and kinetic fragility follow the same order, suggesting that the thermodynamic data alone may be sufficient to determine the kinetic fragility of a liquid. Here we restrict the comparison to a large number of molecular glass-forming liquids, and find breakdowns of the proposed correlation. The absence of an immediate connection between thermodynamic and kinetic fragilities at least in molecular liquids may be due to the effect of kinetic factors and cooperative many-body molecular dynamics. The development of a relation between them requires taking into consideration the cooperative many-body molecular dynamics. The latter governs, in conjunction with thermodynamics, the kinetics of glass-forming liquids, and thus is the missing link between the two.

[1]  K L Ngai,et al.  Similarity of relaxation in supercooled liquids and interacting arrays of oscillators. , 1999, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[2]  K. Ngai.  Synergy of entropy and intermolecular coupling in supercooling liquids , 1999 .

[3]  Kaori Ito,et al.  Thermodynamic determination of fragility in liquids and a fragile-to-strong liquid transition in water , 1999, Nature.

[4]  K. Ngai.  Removal of cooperativity in glass-forming materials to reveal the primitive -relaxation of the coupling model , 1999 .

[5]  Ranko Richert,et al.  Dynamics of glass-forming liquids. V. On the link between molecular dynamics and configurational entropy , 1998 .

[6]  O. Yamamuro,et al.  Calorimetric Study of Glassy and Liquid Toluene and Ethylbenzene: Thermodynamic Approach to Spatial Heterogeneity in Glass-Forming Molecular Liquids† , 1998 .

[7]  R. Böhmer,et al.  Dielectric relaxation in the fragile viscous liquid state of toluene , 1997 .

[8]  P. Lunkenheimer,et al.  Fast Dynamics in CKN and CRN Investigated by Dielectric Spectroscopy , 1997 .

[9]  C. Jackson,et al.  Vitrification and Crystallization of Organic Liquids Confined to Nanoscale Pores , 1996 .

[10]  M. Mizukami,et al.  Calorimetric study of 1,3-diphenyl-1,1,3,3-tetramethyldisiloxane: Emergence of α-, β-, and crystalline-glass transitions , 1996 .

[11]  O. Yamamuro,et al.  CALORIMETRIC STUDY OF 3-BROMOPENTANE : CORRELATION BETWEEN STRUCTURAL RELAXATION TIME AND CONFIGURATIONAL ENTROPY , 1995 .

[12]  M. Hanaya,et al.  Discovery of a potentially homogeneous-nucleation-based crystallization around the glass transition temperature in salol , 1995 .

[13]  K. Ngai,et al.  Junction dynamics and the elasticity of networks , 1994 .

[14]  C. Angell,et al.  Nonexponential relaxations in strong and fragile glass formers , 1993 .

[15]  C. Angell.  Relaxation in liquids, polymers and plastic crystals — strong/fragile patterns and problems☆ , 1991 .

[16]  R. Cole,et al.  Approach to glassy behavior of dielectric relaxation in 3‐bromopentane from 298 to 107 K , 1986 .

[17]  A. B. Bestul,et al.  Heat Capacity and Thermodynamic Properties of o‐Terphenyl Crystal, Glass, and Liquid , 1972 .

[18]  G. Adam,et al.  On the Temperature Dependence of Cooperative Relaxation Properties in Glass‐Forming Liquids , 1965 .

[19]  W. Kauzmann.  The Nature of the Glassy State and the Behavior of Liquids at Low Temperatures. , 1948 .