Optical Properties in Cadmium Borosilicate Glasses
CdO-B2O3-SiO2系ガラスの光学物性に関する研究

Yoshinari MIURA, Koichiro KATAOKA, Katsuaki TAKAHASHI
1986 Journal of the Ceramic Association Japan  
Now with Nippon Steel Co Photochromism and photoconduction were investigated on the system CdO-B2O3-SiO2. The optimum photoresponse was determined for various systematic substitutions. By irradiation of the darkening light having a wavelength near the absorption edge, an additional absorption was induced over almost the whole visible region. The photoinduced absorption lasted for a long time and its half fading time was 17h at room temperature in the dark. The optimum composition for
more » ... sm was near the composition, 58 CdO25B2O317SiO2 (mol%). Appreciable photocurrents were also observed as reported by Caslavska et al., showed the best photoconductioe property. The electric conduction of these glasses was found to be electronic by thermoelectric power measurement, and the activation energy for electric conduction was around 1.8eV which was almost equal to half the optical gap. The compositional changes of photoconduction showed the opposite tendency to those of photochromism. In other words, the glasses exhibiting remarkable photoconduction had a weak photochromic property and vice versa. ESR measurements before and after exposure to UV light indicated that Cd+ ions (g 1.998) were responsible for the photochromic behavior. The ESR signal of Cd+ ions became larger with increasing photochromic property. On exposing to UV nonbridging oxygens bonding to a Cd2+ ion acted as electron donors and an activated electron was trapped by the Cd2+ ion. In the glass systems where R2+1/2-OSiO3 and R2+1/2BO4 tetrahedron and R21/2-OBO2 triangle coexisted, photochromic property became larger because electrons of oxygens localized due to steric hindrance, therefore, nonbridging oxygens donated an electron readily to Cd2+ ion. On the other hand, in the glass systems where many R2+1/2-OBO2 units and few R2+1/2-OSiO3 units coexisted, photochromic property became weaker because electrons of oxygens delocalized due to the B-O bon di nes [ Rec
doi:10.2109/jcersj1950.94.1087_365 fatcat:wr25ojkmqrcnlhzvfvtpy4l46q