Long lasting phosphorescence of calcium aluminosilicate glasses doped with Eu2+
Kawasaki Mitsuharu; Tanabe Setsuhisa; Tanaka Katsuhisa; Qiu Jianrong; Hirao Kazuyuki
Abstract:Long lasting phosphorescence has been observed in CaO Al2O3 SiO2 glasses doped with Eu2+ and Nd3+ after irradiation with an Hg lamp. The emission is due to the 4f 5d transition of Eu2+. The phosphorescence wavelength varies from 500 to 600 nm, depending on the glass composition. The variation of phosphorescence wavelength is caused by the change of environment around Eu2+ ions with glass composition. Analyses of thermoluminescence glow curves reveal that the depth of electron or hole trap level which contributes to the phosphorescence process ranges from 0.50 to 0.81eV. It is thought that these are suitable values for the occurrence of thermoluminescence at around room temperature which results in the long lasting phosphorescence. Key Words:long lasting phosphorescence, thermoluminescence, glass, Eu2+, trap level