Laser-Induced Optical Kerr Effect and the Dynamics of Orientational Order in the Isotropic Phase of a Nematogen

The transient order induced in the isotropic phase of the $N{-}(p{-}Methoxybenzylidene){-}p{-}butylamine$ by the plane-polarized electric field of a $Q$ -switched laser beam, is experimentally measured and analyzed. Good agreement is found with considerations deduced from the theory of de Gennes. It allows direct measurements of the optical Kerr constant and of the orientational relaxation time in these materials.