C-13 NMR spectra of styrene/butyl methacrylate copolymers prepared in bulk at 125degreesC using 2,2,6,6-tetramethyl-1-(1-phenylethoxy)piperidine as the initiator were analyzed. After assignment of the carbon resonances of the aromatic C-1 region, the Mayo-Lewis terminal model (MLTM) was tested by comparison of experimental and predicted values of configurational triad sequences. It follows that MLTM provides an excellent prediction across a wide conversion range for all comonomer feeds.