Solid state C-13 n.m.r. measurements were carried out on polymer networks based on methyl methacrylate and diethylene-glycol-bis-allyl-carbonate. Several relaxation time parameters (rotating frame and laboratory frame proton and carbon relaxation times) were determined. Cross-polarisation times and carbon relaxation times were interpreted based on the changes in the molecular motion during the curing process. Proton relaxation times were interpreted based on the heterogeneity of the matrix. Results confirmed phase separation at complete conversion.