Thermal polymeric initiators, having pendant 1,2-bis(trimethylsilyloxy)tetraphenylethane (or benzopinacolate) groups along the chain, have been prepared. First, the reactivity ratios of 4-vinylbenzophenone (4VBP) and 4-methacryloyloxybenzophenone (MOB) copolymers with styrene or methylmethacrylate were determined. Then the randomly containing 4VBP or MOB copolymers were transformed into polymeric initiators by duplication reaction of the attached benzophenone. Polymerization of MMA or St initiated by the resulting copolymers having pendant benzopinacolate groups was carried out yielding PMMA-g-PS and PS-g-PMMA.