High-pressure and temperature dependence of dielectric relaxation in supercooled di-isobutyl phthalate

Results are presented for isothermal, high-pressure (up to p=300 MPa), and temperature (under atmospheric pressure) measurements of complex dielectric permittivity in supercooled di-isobutyl phthalate. The relaxation times determined from the temperature study obey the temperature Vogel-Fulcher-Tammann (VFT) law. The pressure dependence of relaxation times describes the relation tau=tau(0)exp[B/(p-P-o)] This equation gives the same ideal glass transition pressure po as the generalized VFT formula proposed by Leyser et al. [Phys. Rev. E 51, 5899 (1995)]. For isobaric and isothermal absorption curves, the scaling behavior has been also tested.