We observed the neutron scattering of mixtures of deuterated and normal polystyrene in bulk for samples (strips) undergoing a stress relaxation after a step-strain. Some samples were just melt (i.e. molten at T > Tg=100°C), others were crosslinked and thus some were rubbers at T > Tg. The scattering measured at different times elapsed after the step-strain gives access to the dynamics at the submolecular scale (300-10 A). It is compared with the theoretical predictions that one may extract from the classical models. Observed discrepancies are tentatively interpreted following several “remarks” on the topology of the network and the possible mechanisms of deformation at the corresponding scales.