title: Simple nonlinear equation for structural relaxation in glasses.
abstract: A wide range of glassy and disordered materials exhibit complex, nonexponential, structural relaxation (aging). We propose a simple nonlinear rate equation δ = a[1-exp(b δ)], where δ is the normalized deviation of a macroscopic variable from its equilibrium value, to describe glassy relaxation. Analysis of extensive experimental data shows that this equation quantitatively captures structural relaxation, where a and b are both temperature- and, more importantly, history-dependent parameters. This analysis explicitly demonstrates that structural relaxation cannot be accurately described by a single nonequilibrium variable. Relaxation rates extracted from the data imply the existence of cooperative rearrangements on a supermolecular scale.
authors.affiliation: Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem 91904, Israel.
authors.forename: Itamar
authors.initials: I
authors.lastname: Kolvin
authors.forename: Eran
authors.initials: E
authors.lastname: Bouchbinder
mesh_terms: D003198:Computer Simulation; D005898:Glass / Q000737:chemistry*; D008956:Models, Chemical; D017711:Nonlinear Dynamics; D044367:Phase Transition; D012212:Rheology / Q000379:methods*