Analysis of the temperature dependence of the structural relaxation time τα( T ) in supercooled liquids revealed a qualitatively distinct feature—a sharp, cusplike maximum in the second derivative of log τα(T ) at some Tmax. It suggests that the super-Arrhenius temperature dependence of τα(T ) in glass-forming liquids eventually crosses over to an Arrhenius behavior at T <Tmax , and there is no divergence of τα(T ) at nonzero T . Tmax can be above or below Tg, depending on the sensitivity of τ ( T ) to a change in the liquid's density quantified by the exponent γ in the scaling τα(T )∼exp (A /T ρ-γ) . These results might turn the discussion of the glass transition in a different direction—toward the origin of the limiting activation energy for structural relaxation at low T .
Physical Review E
- Pub Date:
- December 2015
- Theory and modeling of the glass transition;
- Glass transitions of specific systems;
- Condensed Matter - Soft Condensed Matter