Gamma ray interaction with lithium diborate glasses containing transition metals ions

UV-visible spectroscopy of undoped and TM-doped (Ti-Cu) lithium diborate glasses have been measured before and after successive gamma irradiation. In the undoped borate glass, strong charge transfer UV bands are observed at 235 and 280 nm which are related mostly to trace iron impurities (Fe3+) ions. In the TM-doped glasses, characteristics absorption bands are obtained due to each specific TM ion in addition to that due to the base glass. Gamma irradiation produced induced bands due either to the intrinsic host borate glass in the UV region at about 210, 230, 280 nm and one visible band at 540 nm or extrinsic bands which are different according to the added TM ions and initiated by photochemical processes. The rate of induced color centers formation is fast at first and then becomes slower or reaches saturation and some TM ions (V, Cr, Co, Ni, Cu) show retardation or shielding to gamma ray but with varying degrees. Infrared absorption measurements of the undoped and TM-doped glasses are measured to justify the structural groups of the host lithium borate glass and the effects of TM ions on their arrangement. Gamma irradiation causes a decrease in the intensities of the IR bands accompanied by losing sharpness. These features are related to more amorphicity or disorder by irradiation or to the possible changes in bond angle or bond length in the building groups arrangement. (C) 2007 Published by Elsevier B.V.