Comparison of the viscoelastic, dielectric and light scattering properties of benzyl benzoate

Abstract

Measurements have been made of the viscoelastic and dielectric properties of benzyl benzoate in the supercooled state. From the results the values of the viscoelastic retardation time, τ_r, the relaxation time, τ_m, and the dielectric relaxation time τ_D, have been determined. These times are compared with the relaxation time τ_c, obtained from investigations of the depolarised doublet of scattered light. The retardational modulus, G_r, and the infinite frequency shear modulus, G_∞, are also compared with the modulus, µ_∞ from light scattering experiments.

It is shown that τ_c and µ_∞ are similar to (or possibly identical to), the retardation properties τ_r and G_r respectively, and not to the relaxational time τ_m and G_∞. In the low viscosity region τ_D= 5.5 τ_m and τ_c= 11 τ_m. In the supercooled region τ_r= 182 τ_m, τ_D= 11 τ_m, and the dielectric and retardational properties are described by Davidson–Cole equations each with the time distribution parameter β= 0.5.