Laser and Electric Field Induced Birefringence Studies on the Cyanobiphenyl Homologues

Abstract

The optical and d.c. pulsed field Kerr Effects have been used to study the pretransitional behaviour in the isotropic phase for the alkyl cyano-biphenyl homologues (CN φ.φ C_nH_2n+1) for n = 5–8. From the dynamic and static measurements both the relaxation time (τ) and the Kerr Constant B have been found to be proportional to (T-T*)⁻¹. These results are interpreted in terms of the Landau - de Gennes model and the characteristic parameters of this formalism have been given. The results are discussed in terms of the changing chemical structure.