Molecular dynamics of the supercooled liquid state. Low frequency dielectric relaxation of benzophenone, cyclohexanone and fenchone in o-terphenyl

Abstract

A detailed study of the low frequency dielectric relaxation of dilute solutions of benzophenone, cyclohexanone and fenchone in o-terphenyl in the supercooled liquid state shows (i) that only a part of µ² is relaxed by the low frequency cooperative process (ii) the cooperative process is quantitatively similar in frequency/temperature location and shape to that observed for anthrone, phthalic anhydride and camphor in o-terphenyl, (iii) the shape of the dielectric loss curves may be represented by the Williams–Watts empirical relaxation function and (iv) that the defect diffusion model for cooperative relaxation proposed by Phillips, Barlow and Lamb gives a quantitative representation of the derived experimental dipole correlation function for benzophenone, and is also fairly satisfactory for cyclohexanone and fenchone.