  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.
