Viscosity and Excess Entropy of As2S3

Abstract

This study presents a critical evaluation of experimental data on the heat capacity and viscosity of arsenic trisulfide and establishes a connection between these properties through excess entropy. As2S3 is a prototypical chalcogenide glass-former, renowned for its exceptional glass-forming ability and high glass stability. The work consolidates an extensive body of literature data on both the viscosity and heat capacity of this material, supplemented by accurate experimental viscosity measurements. The comprehensive analysis of these data enables the development of equations that characterize the viscosity over 14 orders of magnitude and describe heat capacity for crystal, glass, undercooled melt, and melt from 2 to 700 K. These representative equations for heat capacity enable the calculation of excess entropy, whose temperature dependence is subsequently linked to the temperature dependence of viscosity. The results demonstrate a strong correlation between viscosity and excess entropy, as described by the excess entropy model derived from Adam-Gibbs theory, where excess entropy is used in place of configurational entropy. Finally, the results are compared and correlated with prior findings for selenium and As2Se3, providing broader insights into the behavior of chalcogenide glass-formers.