Measurements are described involving neutron spin echo and quasi-elastic light scattering in an end-linked polyfluorosilicone (PFS) gel swollen in acetone as well as in the equivalent solution. Small-angle elastic neutron scattering measurements were performed on the same system. For the PFS-acetone system, both dynamic light scattering and neutron spin echo yield similar results for the characteristic relaxation rates and for the intensity scattered by concentration fluctuations. It is shown that the relaxing part of the spin echo decay is described by the same thermodynamic concentration fluctuations that define the osmotic modulus of the system. Both the collective diffusion coefficient and the intensity of the dynamically scattered light are found to be greater in the gel than in the solution. This difference indicates that the polymer solvent friction coefficient in the cross-linked network is lower than in the un-cross-linked solution.