The influence of irradiation on the microhardness and photoluminescence of SiO2
Abstract
The microhardness and photoluminescence spectra excited with 337-nm laser radiation in commercial SiO2 glasses (UV windows, substrates with BaTiO3 film coatings) exposed to 60Co gamma radiation and a mixed neutron flux from the reactor are investigated. It is revealed that initial samples contain nanocrystalline phases. An increase in the microhardness and the intensity of the excitonic UV luminescence due to 60Co gamma irradiation and the quenching of the photoluminescence associated with the nonbridging oxygen centers result from healing of Si-O dangling bonds and microcracks in the surface layer at the nanocrystal-glass matrix and substrate-coating interfaces. It is demonstrated that reactor irradiation leads to the phase transformation of SiO2 cristobalite into tridymite and BaO into BO2, as well as to the decomposition of BaTiO3 and BaCO3. This brings about a decrease in the microhardness and photoluminescence quenching.