ESR studies on heterogeneous processes in irradiated SiO2/B2O3+H2O systems

Effect of B³⁺ (%B₂O₃) percentage ratio in silica gel on the nature and the mechanism of defect formation and yields of paramagnetic radiation centers (PC) have been studied. The nature of paramagnetic radiation centers of electron hole type has been revealed and their behavior has been investigated as a function of temperature changes. It has been found that the interaction between paramagnetic centers formed at SiO₂/B₂O₃ surface with absorbed water molecules (=1) leads to the formation of H and OH radicals. In addition the experiment shows that increased B³⁺ (%B₂O₃) percentage ratio in silica gel results in higher yields of paramagnetic centers and H-radicals. Possible mechanism of formation, localization and annihilation of non-equilibrium charge carriers (NCC) and their energy transfer to the adsorbed phase has been suggested.