Dielectric Studies in Solid Phase EBBA

Abstract

Dielectric measurements have been made in the stable and metastable solid phases of EBBA in the frequency range 0.1 KHz to 100 KHz and in the temperature range -170 to -10°C.The dielectric dispersion was absent in the stable phase while in the metastable phase, obtained by rapid cooling, a clear dielectric dispersion was seen. In addition to the primary dispersion extending above about -125°C there also appears a clear secondary dispersion region below -125°C. The strength of the second dispersion is lower by one order of magnitude than the primary dispersion. The primary dispersion is of the Debye type with a symmetric distribution of relaxation times. The Cole-Cole distribution parameter varies with temperature and shows a maximum at about -64°C. The results in the primary dispersion region can be qualitatively explained by assuming the free rotation of dipoles above -64°C and a restricted rotation of dipoles at low temperatures.