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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 (?) or viscosity (?), 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. The simple and non-biased way of determining V_a(P) and the relation for its parameterization are proposed. The derived relation resembles Murnaghan - O'Connel equation, applied in deep Earth studies. It also offers a possibility of estimating the pressure and volume at the absolute stability limit. The application of the methodology is shown for diisobutyl phthalate (DIIP, low-molecular-weight liquid), isooctyloxycyanobiphenyl (8*OCB, liquid crystal) and bisphenol A/epichlorohydrin (EPON 828, epoxy resin), respectively.

SUBMITTER: Drozd-Rzoska A

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

REPOSITORIES: biostudies-literature

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Activation volume in superpressed glass-formers.

Drozd-Rzoska Aleksandra A

Scientific reports 20190924 1

In pressurized glass-forming systems, the apparent (changeable) activation volume Va(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 Va(P) = V#(P), where [Formula: see text] or [Formula: see text]. This report shows that Va(P) ≪ V#(P) for P → Pg, where Pg denote ...[more]

PMID: 31551437

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Activation volume in superpressed glass-formers.

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Activation volume in superpressed glass-formers.

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