Equilibrium textures in main-chain liquid crystalline polymers

We analyse the Schlieren textures formed by the nematic director in a therm otropic main-chain liquid crystalline polymer. After an initial coarsening, the textures reach a stable time-independent state which appears to bf an equilibrium function of temperature and material parameters, with a charact eristic length scale xi of order 2 mu m. In particular, we study the evolut ion of this domain size when the temperature approaches the nematic-isotrop ic transition T-ni. The texture size xi increases towards T-ni, but decreas es reversibly when the temperature decreases back into the nematic phase. W e discuss possible theoretical models that may explain such an equilibrium polydomain state of nematic director and the dependence of its size on the nematic order parameter.