Using electron spin resonance spectroscopy, we have studied the kinetics of the bimolecular decay of methacrylic macroradicals in networked and unnetworked polymeric matrices. We have determined that macroradical decay in the entire range of temperatures (20-70 degrees C) is definitely ordered to a second-order kinetic reaction equation. We have estimated the activation parameters of the process. Using Smolukhovsky's and Einstein's equations and the fractal dependence of the conformation radius of the macroradical on its polymerization degree, we have obtained an equation for the constant of bimolecular radical decay under diffusion conditions. This equation is in good agreement with all the experimental data and possesses a commonness permitting its use in the analysis of bimolecular chain termination in different reaction zones via polymerization processes until high conversions.