Chromophore relaxation is still one of the major problems with NLO polymers. One strategy to overcome this problem is the synthesis of polymers with high glass transition temperatures. We have prepared a number of polymers by copolymerization of NLO-active methacrylates with the bulky adamantyl methacrylate. This leads to polymers with glass transition temperatures up to 190 degrees C. The synthesis and properties of these polymers are reported in detail. The polymers show a good long term stability of the electrooptic coefficient (r(33)) at elevated temperatures. So polymer 3c with a bisazo chromophore shows only a 25% EO-coefficient decay after one month at 120 degrees C.