Linear hybrid block copolymers of polydimethylsiloxane (PDMS) and polystyrene (PS) were synthesized using living sequential anionic polymerization. Sample films of these block copolymers were thermally annealed for 48 hr at 120 degrees C to promote phase segregation and allow for the preferential surface segregation of PDMS. The films were then exposed to corona discharge for 30 min. Optical microscopy and scanning electron microscopy (SEM) were used to identify surface cracks due to the formation of a silica-like glassy layer after corona exposure. Slow positron beam studies were used to evaluate the degradation phenomenon and provide the first evidence of silica-like degradation layers forming on the surface of PDMS containing hybrid polymer films, after corona exposure. It also allowed determination of the thickness of the glassy layer. Contact angle measurements also showed the first evidence that the same hydrophobic loss and recovery phenomenon for the corona treated hybrid polymer films occurs, as with pure PDMS samples.