A high Tg acrylic copolymer includes methyl methacrylate with one or more high Tg hydrophobic monomers. The copolymer includes: a) at least one of tert-butyl cyclohexyl methacrylate, 3,3,5-trimethylcyclohexyl(meth)acrylate, tetrahydrofurfuryl methacrylate, or a mixture thereof; and b) (meth)acrylate monomer. The copolymer has the following properties: i) Tg of from 116° C. to 140° C.; ii) Mw of at least 110,000; and iii) a residual monomer level of less than 1.0 weight percent. The copolymer exhibits high heat resistance, high light transmission, low haze, low moisture uptake, excellent environmental stability, excellent high temperature thermal stability, and excellent mechanical properties, along with excellent UV resistance. The high molecular weight hydrophobic copolymer of the invention has the excellent environmental stability required for electronic components in automotive, displays, smartphones, photovoltaics, and others.