This invention concerns transparent polymer mixtures that can be processed thermoplastically consisting of (A) polycarbonates, particularly Bisphenol A polycarbonates, and (B) copolymers of methyl methacrylate and 5 to 40 wt. % of N-substituted maleimides, with the substituent on the imide nitrogen being an optionally substituted cyclohexyl group, in which the copolymer (B) can also be made up of other .alpha.,.beta.-unsaturated monomer units in amounts of 0 to 40 wt. %.