Physical Properties of Aromatic Hydrocarbons. I. Viscous and Viscoelastic Behavior of 1:3:5-Tri-α-Naphthyl Benzene

Abstract

The torsional creep and creep recovery behavior of amorphous 1,3,5‐tri‐α‐naphthyl benzene was studied, while at metastable equilibrium density, along a specified glassy volume—temperature line, and during isothermal volume contraction below the conventional glass transition temperature Tg. Dilatometric measurements confirmed the conventional Tg to be 69°C. The viscosity measurements of Magill and Ubbelohde were extended from 185°C to below Tg, covering viscosity values from 10−1 to 1016 P. In a region of time scale the mechanical response was found to be dominated by Andrade creep. The retardation spectrum found was over 9 logarithmic decades wide in contrast to reportedly narrow spectra exhibited by other liquids with similar molecular weights. A steady‐state compliance Je of 2.6×10−10 cm2/dyn at 64.2°C was measured. Although compliances as low as 8×10−11 cm2/dyn were measured, no time‐independent glassy compliance Jg could be ascertained. Free‐volume theory was found applicable to all measurements made below 120°C. The occupied volume v 0 was deduced to be temperature insensitive.