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.