Stray-held magnetic resonance imaging (m.r.i.) has been used to study the ingress of methanol and methanol-acetone vapour mixtures into poly(methyl methacrylate), PMMA. For pure methanol, the polymer concentration and H-1 spin-spin relaxation time is found to be constant across the swollen region. The relaxation time is, however, greater by a factor of 1.1 compared to the rigid polymer. For mixed solvents, the polymer chain spin-spin relaxation time is greater by factors ranging from 1.1 to 1.4 across the swollen region in samples exposed to solvent for up to 1 week, providing evidence for a spatial gradient in the polymer chain dynamics. Small polymer concentration gradients are also seen in samples exposed to methanol-acetone mixtures. In further experiments, stray field imaging and gradient spin echo diffusion techniques have been combined for the first time in order to make high spatial resolution measurements of the solvent self-diffusion coefficient. These experiments yield complementary spatial gradients in the diffusion coefficient such that the diffusion coefficient typically varies by a factor of 2 across any one sample, ranging from 0.15 to 0.30 x 10(-6) cm(2) s(-1) over 0.8 mm for pure methanol in PMMA and front 1.8 to 3.2 x 10(-6) cm(2) s(-1) over 1.5 mm for 70% methanol-30% acetone. These results are discussed in the context of previous liquid-state m.r.i. investigations of the solvent alone in similar systems.