  We present experimental results for spinodal decomposition in polymer
mixtures of gelatin and dextran. The domain growth law is found to be
consistent with t^1/4-growth over extended time-regimes. Similar results are
obtained from lattice simulations of a polymer mixture. This slow growth arises
due to the suppression of the bulk mobility of polymers. In that case, spinodal
decomposition is driven by the diffusive transport of material along domain
interfaces, which gives rise to a t^1/4-growth law.
