Abstract
This contribution presents the extended, pressure-related Vogel–Fulcher–Tammann equation applied to portray the pressure evolution of viscosity η (P) and the related dynamic properties, such as the primary relaxation time τ (P), in soft-matter systems as well as the modified Simon–Glatzel-type equation for describing pressure dependences of the glass temperature T
g (P), the melting temperature T
m (P) and the fragile-to-strong dynamical transition in confined water T
d
(P). Both equations are capable of penetrating the negative pressure (isotropically stretched liquid) domain, and at very high pressures are capable of the inverse behavior. They have the following forms: (i) η (P)=η0 exp [D
P Δ P/(P
0−P)]=η0 exp [(D
P
P−D
P
P
SL)/(P
0−P)], where P
0 is the estimate of the ideal glass temperature, P
SL is for the stability limit at negative pressures and D
P denotes the pressure fragility strength coefficient and (ii) , where
and
are the reference temperature and pressure,−π is the negative pressure asymptote and c is the damping coefficient responsible for the inversion phenomenon.
Acknowledgement
This work was supported by Ministry of Science and Education (Poland), grant N202 231737.