Molecular Dynamics and Crystallization Behavior of Chiral Isooctyloxycyanobiphenyl as Studied by Dielectric Relaxation Spectroscopy

The complex dielectric permittivity of right-handed isooctyloxycyanobiphenyl (IOOCB) has been studied in the frequency range 10-1−105 Hz and over a wide temperature range. On cooling the isotropic liquid a supercooled liquid is formed that becomes a glass below 220 K. On heating the glass, the material crystallized at about 250 K and remelted at 285 K. The dielectric α-relaxation in the isotropic liquid was found to conform with the Vogel−Fulcher Tamman equation for its average relaxation time and the Kohlrausch−Williams−Watts function for its spectral line shape. The isothermal crystallization of the supercooled liquid to form a crystalline solid was monitored by dielectric relaxation spectroscopy, and the Avrami exponent was found to be 1.51 at a crystallization temperature of 263 K.