Dynamic effects affecting the EPR spectra of radicals trapped in photopolymerized multifunctional acrylate monomers

Two main interpretations are proposed in the literature for the EPR spectra due to radicals produced during the photopolymerization of multifunctional monomers. Different beta-methylene proton configurations undergo fast exch ange in the "dynamic" model, whilst they simply coexist in the "static" mod el. We report nea experimental results suggesting that both the proposed mo dels are valid, though in different physical situations.