Viscoelastic relaxation in supercooled eugenol

Abstract

Measurements have been made of the viscosity, density, and shear mechanical resistance of eugenol. The relaxational behaviour is described in terms of the complex shear compliance J*(jω)=J∞+ 1/jωη+J_r/(1 + jωτ_r)β with the parameters J_r/J_∞= 1.0, ηJ_∞/τ_r= 2.0 and β= 0.5. The corresponding spectrum of relaxation times contains a single relaxation time together with a separate continuous distribution of relaxation times. It is shown that the existence of a single relaxation time in the spectrum is a general feature of the relaxation spectrum for this form of equation. For eugenol, the single relaxation time, τ_t, is found to be 4.28τ_r. The fractional contribution to the viscosity, η_t/η, and the relaxable shear modulus, G_t/G_∞, due only to the single relaxation process are 93 % and 43 % respectively.