Kinetics of Photoinduced Radical Polymerization with Electron Donor/Electron Acceptor Initiator SystemsBy means of benzyltriphenylphosphonium tetrafluoroborate (P⊕) and anthracene (An) as photoinitiator system and methylmethacrylate (MMA) as monomer the influences of several reaction parameters on the polymerization quantum yield Φp, were studied. The following principal reactions proceed: electron transfer between excited An (1An) and P⊕salt (kq= 2,5 · 109M−1s−1), quenching of1An by MMA (k qMMA= 1,3 · 107M−1s−1), reaction between a1An…P⊕salt complex and MMA. The last reaction is assumed, since from the disappearance of An and the formation of An cation radical, respectively, rate constants k qMMA>108M−1s−1have been calculated. Furthermore, it is assumed, that only the quenching of1An by MMA (Φp= 3,8) and the addition of free radicals, produced by the photoinduced electron transfer, lead to polymer formation. Kinetic equations were developed, which can explain the effect of P⊕‐salt concentration, light intensity and MMA concentration on Φpdata. The quotient obtained for kp/k t0,5is in the range of 0,053 to 0,087 M−0,5s−0,5, depending on the used experimental parameters. Polymerization degrees Pnof 260–590 were found, which al