Polycarbonates suitable for use in optical articles

摘要

This invention provides certain polycarbonates and polycarbonate blends useful in optical article applications. In a preferred embodiment, copolymers of, for example, certain ortho substituted bisphenol A-based polycarbonates and bisphenol A, optionally further comprising polycarbonate residues derived from ortho subsitituted spirobiindane compounds and alkylene or cycloalkylene diacid moieties. In a further embodiment, the invention provides copolymers of certain ortho-substituted bisphenol A moieties and ortho-substituted spirobiindane moieties. Also provided are optical articles comprised of the copolymers and blends of the invention. We have found that such copolymers and blends exhibit superior dimensional stability when exposed to water or moisture.