Flexible high refractive index, cross-linked, acrylic copolymers

A copolymer having a glass transition temperature less than about 37.degree. C. and an elongation of at least 150%, consisting essentially of 2 monomers of the formula:

• ##STR4## wherein X is H or CH.sub.3 ;
• m is 1-10;
• Y is nothing, S, or NR wherein R is H, CH.sub.3, C.sub.n H.sub.2n+1, iso OC.sub.3 H.sub.7, C.sub.6 H.sub.5, or CH.sub.2 C.sub.6 H.sub.5 ;
• n is 1-10;
• Ar is an aromatic ring which can be unsubstituted or substituted with H, CH.sub.3, C.sub.2 H.sub.5, n-C.sub.3 H.sub.7, iso-C.sub.3 H.sub.7, OCH.sub.3, C.sub.6 H.sub.11, C.sub.6 H.sub.5 or CH.sub.2 C.sub.6 H.sub.5 ;
• wherein one monomer is an acrylate and one monomer is a methacrylate and wherein the acrylate monomer is present in an amount greater than the methacrylate monomer;
• and
• a copolymerizable cross-linking monomer having a plurality of polymerizable ethylenically unsaturated groups wherein the cross-linking monomer is present in an amount no greater than 10% by weight.