Entropy Basis for the Thermodynamic Scaling of the Dynamics of OTP

Abstract

Structural relaxation times and viscosities for non-associated liquids and polymers are a unique function of the product of temperature, T, times specific volume, V, with the latter raised to a constant, g_tau. Similarly, for both neat o-terphenyl (OTP) and a mixture the entropy for different T and pressures, P, collapse to a single curve when expressed versus TV^g_s, with the scaling exponent for the entropy, g_s, essentially equal to the thermodynamic Gruneisen parameter. Since the entropy includes contributions from motions, such as vibrations and secondary relaxations, which do not affect structural relaxation, g_s < g_tau. We show herein that removal of these contributions gives a satisfactory accounting for the magnitude of g_tau. Moreover, the relaxation times of OTP are found to be uniquely defined by the entropy, after subtraction from the latter of a V-independent component.

12 pages 3 figures V Workshop on Non Equilibrium Phenomena in Supercooled Fluids, Glasses and Amorphous Materials 17 - 22 September 2006, Pisa, Italy

References in corpus (4)

• Thermodynamic Scaling of the Viscosity of Van Der Waals, H-Bonded, and Ionic Liquids
• Thermodynamic interpretation of the scaling of the dynamics of supercooled liquids
• Scaling of the Local Dynamics and the Intermolecular Potential
• Slow dynamics of salol: a pressure and temperature dependent light scattering study

Cited by in corpus (13)

• Pressure-energy correlations in liquids. III. Statistical mechanics and thermodynamics of liquids with hidden scale invariance
• Strong pressure-energy correlations in liquids as a configuration space property: Simulations of temperature down jumps and crystallization
• Density scaling as a property of strongly correlating viscous liquids
• Hidden scale invariance in molecular van der Waals liquids: A simulation study
• Heat capacity at the glass transition
• Determination of the Thermodynamic Scaling Exponent from Static, Ambient-Pressure Quantities
• Equation of State and Entropy Theory Approach to Thermodynamic Scaling in Polymeric Glass-Forming Liquids
• Connection between dynamics and thermodynamics of liquids on the melting line
• Density scaling of the diffusion coefficient at various pressures in viscous liquids
• Correlation of the scaling exponent of the diffusivity-density function in viscous liquids with their elastic properties
• Role of entropy in the thermodynamic evolution of the time scale of molecular dynamics near the glass transition
• A plausible interpretation of the density scaling of the diffusivity in viscous liquids
• Variation along liquid isomorphs of the driving force for crystallization