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Influence of a long-chain alkane on the photoinduced nematic-isotropic transition
Phys. Rev. E 69, 021708 – Published 27 February, 2004
DOI: https://doi.org/10.1103/PhysRevE.69.021708
Abstract
We investigated the phenomenon of photoinduced nematic-isotropic transition for different concentrations of a long-chain alkane, viz., octadecane (OD), and a host liquid crystalline material having a small quantity (4.5 mol %) of a photoactive azo compound. As expected, the transition temperature diminishes with increasing concentration of OD. Data of time-resolved measurements of the dielectric constant through both the UV-activated trans-cis transformation and the thermal back relaxation process are presented. With increasing concentration of OD, although the response time for the former process increases slightly by less than a factor of 2, the thermal back relaxation shows a greater increase by more than an order of magnitude. As a possible explanation for this surprising result, we discuss an argument based on the structural incompatibility of the constituents of the system investigated.
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