Dielectric relaxation study of formamide-propylene glycol using time domain reflectometry

Using picoseconds time domain reflectometry, dielectric relaxation studies have been carried out for formamide (FMD)-propylene glycol (PLG) mixtures over the frequency range from 10 MHz to 20 GHz at various temperatures. The dielectric parameters, i.e. static dielectric constant (epsilon 0) and relaxation time (), have been obtained by Fourier transform and least squares fit methods. The excess dielectric properties and Kirkwood correlation factor of the mixtures have also been determined. The Kirkwood angular correlation factor is greater than one (geff 1) in FMD-rich region and less than one (geff 1) in PLG-rich region, which indicates that in the mixture the dipole pairs have been formed in such a way that their orientation is parallel in FMD-rich region and antiparallel in the PLG-rich region.