Paramagnetic defects in solid sulphur and glasses of the system Ge–S

Ge–S glasses are synthesised by melting pure S and Ge elements. Electron paramagnetic resonance (EPR) spectroscopy is used to analyse the paramagnetic defects in these glasses. Paramagnetic defects are also observed in amorphous and polycrystalline S samples after UV irradiation at T=77 K. The simulation of the EPR spectra leads to spectroscopic parameters of the sulphur centres which are similar in S samples and in S-rich Ge–S glasses, at the liquid nitrogen temperature. In Ge–S glasses, the paramagnetic sites remain stable at room temperature and the spectroscopic parameters are modified. The nature of the sites involved in these absorptions is discussed.