Decay of spatially periodic patterns in a nematic liquid crystal

A detailed theoretical and experimental analysis of the decay of electroconvection patterns is presented in a planarly aligned nematic liquid crystal. The relaxation time is measured as a function of the wave number of the pattern using a light diffraction technique. A theoretical analysis exhibits a rich structure of the dispersion curves for the decay rates. An interesting relation between the realistic case of no-slip boundary conditions and the simpler free-slip case is found. The experimentally determined relaxation rates for both "conductive" and "dielectric" initial patterns follow the theoretical solution with subsequent jumps between branches when the wave number is increased.