Effect of Tb3+ ions on X-ray-induced defect formation in phosphate containing glasses

The study of radiation-induced defect formation in glasses is of growing interest for applications in optics and photonics. The influence of Tb3+ ions on X-ray-induced defects has been examined in glasses with. different phosphate contents. The defects have been characterized by optical absorption and ESR spectroscopy. (Tb3+). ions are formed by X-ray irradiation. They exhibit a broad charge transfer band at 370 nm. The formation of (Tb3+)(+) hole centres suppresses the formation of intrinsic phosphate-related hole centres, absorbing in the visible region. PO3 defects absorbing in the ultraviolet region contribute mainly to the electron centres corresponding to the (Tb3+)(+) hole centres. Immediately after X-ray irradiation, 5-10% of the Tb3+ ions have been oxidized. The amount of (Tb3(+))(+) ions increases with increasing phosphate content. The stability of the (Tb3+)(+) ions at room temperature depends on glass composition and melting conditions. (C) 2002 Elsevier Science B.V. All rights reserved.