  We present theory and simulation of simultaneous chemical demixing and phase
ordering in a polymer-liquid crystal mixture in conditions where
isotropic-isotropic phase separation is metastable with respect to
isotropic-nematic phase transition. In the case the mechanism is nucleation and
growth, it is found that mesophase growth proceeds by a transient metastable
phase that surround the ordered phase, and whose lifetime is a function of the
ratio of diffusional to orientational mobilities. In the case of spinodal
decomposition, different dynamic regimes are observed depending on the mobility
ratio: metastable phase separation preceding phase ordering, phase ordering
preceding phase separation, or simultaneous phase ordering and phase
separation. Not only the overall dynamics but also the final structure of the
material can be different for each kinetic regime.
