A limited play optical storage medium for data is described which comprises a first substrate, a reflective layer, a data layer disposed between said substrate and said reflective layer; a reactive layer comprising at least one carrier, and at least one reactive material, and an optically transparent second substrate comprised of a polymethacrylate copolymer or blend comprising a polymethacrylate copolymer or homopolymer. The second substrate is disposed between the reactive layer and a laser incident surface and is tailored to provide an oxygen permeability in a range between about 0.1 Barrers and about 1.35 Barrers at 25.degree. C.