The overall reaction rate kinetics of polymerization of diethyleneglycol dimethacrylate and copolymerization of it with styrene in bulk and in the presence of inert diluents were investigated. The results indicated that these reactions can be treated as free radical polymerization with highly diffu-sion controlled termination reaction in which the termination rate constant is an empirically derivedfunction of monomer conversion: Kt=Kto(1-c ln[M]/ [M0])-1 in which Kto is the initial termination rate constant and c is a factor related to the magnitude of diffusion contro! The following equantion of monomer conversion as a function of time could then be derived:U=1-exp{1/c[1-(1+ckt/2)2]} in which k=Kp(Ri/2Kt0)1/2 and t is the time of reaction.Excellent agreement between the thoretical and experimental overall reaction kinetic curves was obtained.The equation is valid for crosslinking and noncrosslinking free radical polymerizations in which the self-acceleration effect is effective from the very begining of the reaction.The equantion can be expressed in a more generally applicable form:U=1-exp{1/c[1-1(1+cks/n)n]} in which n ≥0.