Uv Light Induced Photoreduction In Phosphate And Fluoride-Phosphate Glasses Doped With Ni2+, Ta5+, Pb2+, And Ag+ Compounds

The photoreduction of polyvalent ions was studied in high purity fluoride-phosphate and metaphosphate glasses doped with Ni2+ (3d8), Ta5+ (5d0), Pb2+ (6d2), and Ag+ (3d10). Compared to the undoped base glasses, all doped samples display different electronic transitions in the UV at the irradiation wavelength. Glass samples containing 50 to 5000 ppm dopants were irradiated with excimer lasers at 193 and 248nm, respectively. The subsequent defect centres, formed at ppm levels, were characterised by EPR and optical UV-VIS spectroscopy.