Radiation-induced defects in calcium aluminate glasses

In this work, MgF2 and CaF2 doped calcium aluminate glass samples have been investigated in order to describe the intrinsic defects that are formed in UV irradiated glasses. It is well known that calcium aluminate, when UV-illuminated, changes colour from blue to green. Thermoluminescence (TL), Optical Absorption (OA) and Electron Paramagnetic Resonance (EPR) measurements have been carried out and the results obtained were associated with the structural properties of the CaO-Al2O3-SiO2 System, in order to provide a defect model. Thermal treatments up to 150degreesC were performed for OA and TL measurements but the thermal decay curves could not be adjusted by an exponential function. The TL experimental results were fitted, according to a continuous model, with a Gaussian distribution function centred at 0.6 eV and a frequency factor of 10(9) s(-1).