In this paper, we investigate the final morphology of photocured polyurethane acrylates based on polypropylene oxide by means of Transmission Electron Microscopy (TEM), Small Angle X-ray Scattering (SAXS), and dynamic mechanical measurements. Two interrelated structural features on two different size scales can occur in these systems. TEM analysis demonstrates the presence of inhomogeneities on the length scale of 10-200 manometers, mostly constituted by clusters of small hard units (diacrylated diisocyanate) connected by polyacrylate chains. The bimodal shape of the dynamic mechanical relaxation spectra corroborates this two-phase structure. Besides, a suborganization of the reacted diisocyanate hard segments inside the polyurethane acrylate matrix is revealed by SAXS measurements, depending on the nature of the hydroxylacrylate used for the synthesis of the precursor. Finally, W-exposure time is found to induce modifications on the viscoelastic properties of the final network, even at high double-bond conversion: this effect can be due to a postreaction and to an increase of the crosslinking density inside the hard segments domains.