Direct Test of Supercooled Liquid Scaling Relations

Abstract: Diverse material classes exhibit practically identical behavior when made viscous upon cooling toward the glass transition, suggesting a common theoretical basis. The first-principles scaling laws that have been proposed to describe the evolution with temperature have yet to be appropriately tested due to the extraordinary range of time scales involved. We used seven different measurement methods to determine the structural relaxation kinetics of a prototype molecular glass former over a temporal range of 13 decades and over a temperature range spanning liquid to glassy states. For the material studied, our results comprise a comprehensive validation of the two scaling relations that are central to the fundamental question of whether supercooled liquid dynamics can be described universally. The ultrabroadband mechanical measurements demonstrated have fundamental and practical applications in polymer science, geophysics, multifunctional materials, and other areas.