The 70SnF//2 center dot 30P//2O//5 glasses containing 25-500 ppm of fluorescein exhibit change in color from light yellow to reddish orange (absorption maximum, lambda equals 500 nm) when heated at 240 degree C for 120-180 min. The fluorophosphate glasses also change the color from light yellow to reddish brown ( lambda equals 480 nm) when irradiated with **6**0Co gamma -rays of 5 multiplied by 10**4 Gy. The P-F stretching mode observed in the Fourier transformed infrared (FT- IR) spectra showed an increase in peak intensity along with the coloration, suggesting a cleavage of the weak chemical bond between fluoride ions (F** minus ) and fluorescein molecules. The coloration is ascribed to change of the molecular structure of fluorescein from non-crystalline to crystalline type. ESR spectra of gamma -ray irradiated 70SnF//2 center dot 30P//2O//5 glasses showed a poorly resolved doublet, which was ascribed to a hole-trapped PO//3F** minus center produced by electron scattering: PO//3F**2** minus yields PO//3F** minus plus e** minus . ( Author abstract) 17 Refs.
Nishida, Tetsuaki Sasaki, Shigeo Toma, Tetsuya Maeda, Yonezo
