Thin film bilayers of deuterated polystyrene (dPS) and blends of deuterated poly(methyl methacrylate) (dPMMA) with a compositionally symmetric random copolymer of styrene and methyl methacrylate (P[S-0.49-ran-MMA]) were investigated by neutron reflectivity. Copolymer segregation to the free surface occurs upon spin-coating blends onto silicon substrates. Annealing the bilayers to equilibrium at 150 degrees C increases the segregation of the copolymer from the blend layers to the interface with dPS. Blends containing 5 and 10 vol % copolymer both exhibit this segregation behavior. For these blend compositions the interfacial segregation of copolymer from the miscible blends is insufficient to form a discrete layer. These results suggest that this random copolymer would be an interfacial specific additive.