The rates of photochemical polymerization of styrene (St), p-chlorostyrene (Cl-St), methyl methacrylate MMA), and butyl methacrylate (BMA) with polymethylphenylsilane (PMPS) as an initiator were measured. Polymethylphenylsilane is photodegrated to form silyl radicals that may initiate polymerization of vinyl monomers. Rate constants k(p) and k(t) have been determined for these systems. A good correlation (log P = alpha + beta mu) Of the resonance stabilization (P) of the chain radicals and the dipole moment (mu) of the monomers is observed for these polymerization systems. This equation may be used to estimate the resonance stabilization (P) of a monomer and the polymerization rate constant (k(p)).