Assignments and optical properties of X-ray-induced colour centres in blue and orange radiophotoluminescent silver-activated glasses

We have systematically investigated the origin and optical properties of the X-ray-induced colour centres based on the blue and red radiophotoluminescence (RPL) in a silver-activated phosphate glass. The induced-absorption band was decomposed into six Gaussian bands on the basis of its strong analogy with silver-activated sodium chloride. We have ascribed these bands to Ag0, Ag2+, image and other silver ion species by means of optical and thermal measurements such as colour centre formation and dissolution by highly successive femtosecond-pulse irradiation, excited-state lifetime and thermal annealing characteristics. The data confirmed that the blue RPL at 450 nm could be attributed to the 270 and 345 nm bands due to the image and Ag0 centres, respectively, and that the orange RPL at 560 nm was associated with the 308 nm band due to the Ag2+ centres.