Gamma-ray irradiation induced bulk photochromism in WO3–P2O5 glass

In the present work, photochromism of WO 3 –P 2 O 5 glass under gamma-ray irradiation was reported. As-prepared glass samples with different WO 3 content are all optically transparent in the visible wavelength range thanks to the addition of a small amount of oxidizing couple Sb 2 O 3 –NaNO 3 . The photochromic properties are identified by transmission spectra of the glasses before and after irradiation. The results show that the irradiation induced darkening results from the reduction of W 6+ to W 5+ or W 4+ . The existence of WO 6 clusters in glasses of high WO 3 content is proved by XPS, which is the main reason for the obvious photochromic effects. The WO 3 –P 2 O 5 glass is a promising candidate in gamma-ray sensitive detector.