Terpolymerizations of styrene, methyl methacrylate, and glycidyl methacrylate in solution with supercritical CO2 were carried out in a tubular reactor up to almost complete monomer conversion. The residence time behavior of the set-up was investigated by injecting a tracer pulse and measuring the tracer concentration at the reactor exit via in-line FT-near infrared (NIR) spectroscopy. Molecular weight control during polymerization was achieved either by initiator concentration or by the addition of a catalytic chain-transfer agent. Number average molecular weights were adjusted to about 2500 g mol−1 to yield products which are suitable components for powder coating applications.