Activation volume in superpressed glass-formers.

ABSTRACT: In pressurized glass-forming systems, the apparent (changeable) activation volume V_a(P) is the key property governing the previtreous behavior of the structural relaxation time (τ) or viscosity (η), following the Super-Barus behavior: [Formula: see text], T = const. It is usually assumed that V_a(P) = V^#(P), where [Formula: see text] or [Formula: see text]. This report shows that V_a(P) ≪ V^#(P) for P → P_g, where P_g denotes the glass pressure, and the magnitude V^#(P) is coupled to the pressure steepness index (the apparent fragility). V^#(P) and V_a(P) coincides only for the basic Barus dynamics, where V_a(P) = V_a = const in the given pressure domain, or for P → 0.

SUBMITTER: Drozd-Rzoska A 

PROVIDER: S-EPMC6760521 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature