Near-critical behavior of the dynamic stress-optical coefficient in liquid crystalline elastomers

Abstract

Dynamic stress-optical measurements on liquid crystalline elastomers with different crosslinking densities have been carried out in the isotropic phase. The appearance of two relaxation processes in the spectra is probably due to the side-on attachment of the spacers to the mesogenic groups. The relaxation frequencies and the relaxation strength of the processes show critical behavior in qualitative agreement with the Landau-de Gennes theory. The strong cross-linking density dependence of the relaxation strengths provides evidence that the cross-linking points locally perturb the liquid crystalline order