Spin-contrast-variation neutron reflectivity can be used to obtain multiple reflectivity curves from a single sample and a single beam source. This advantage of the technique allowed a structural analysis of the interface in a bilayer film comprising layers of acrylic urethane resin and methylated-perhydropolysilazane-derived silica (MePDS). It is revealed that, although the MePDS layer has a higher porosity near the interface with the resin, the resin did not permeate the pore network.