Radical-initiated copolymerization of tri-n-butylstannyl methacrylate (TBSM) with allyl chloroacetate (ACA) was carried out in the presence of benzoyl peroxide as initiator in benzene at 70 degrees C in nitrogen atmosphere. Monomer reactivity ratios of the TBSM (M-1)-ACA (M-2) monomer pair were determined by the Kelen-Tudos method: r(1) = 1.25 +/- 0.02 and r(2) = 0.13 +/- 0.005. From copolymerization kinetic data the Values of effective energy of activation (E-a) and orders with respect to initiator (n) and to monomers (m), E-a = 79.0 kJ/mol, n = 0.51, and m = 1.2, were determined. Photochemical reactions of the copolymer were studied by using monochromatic W-irradiation at 405 nm and FTIR spectroscopy. For the copolymer synthesized the quantum efficiency (phi(crl) = 0.62 mol/Einstein and photosensitivity S = 25.5 cm(2)/J (in the presence of 1,9-dibromoanthracene as a sensitizer) were found. It was shown that the effects observed of the tin atom and Cl substituent via pentacoordinated complex (-R3Sn...O=C-) and sigma(Cl-CH2)-pi(C=O)-pi(allyl) conjugation, respectively, are the main factors for reducing degradative chain transfer and for increasing the tendency of monomers to alternate as well as for the photocrosslinking of copolymer macromolecules. (C) 1998 John Wiley & Sons, Inc.