Study On Preparation And Luminescent Properties Of Germanosilicate Glass

Nowadays, environment and energy crisis have become international issues. The development of new technology is needed for protecting environment. As one of the most favorite energy-saving materials, optical glass has been paid more and more attention by researchers. Germanosilicate optical glass has been widely used for luminescent materials due to its low phonon energy, good ability of glass formation and high rare earth ions solubility. Recent years, germanosilicate optical glass has been recognized as a promising material in the fields of information processing, LSD, military and laser medicine.First, this thesis reviewed the development and application of rare earth ions doped germanosilicate optical glass. Second, the germanosilicate optical glasses and oxyfluoride germanosilicate glass ceramics were prepared by melting-annealing/ quenching/thermal treatment method. The effects of the ratio of SiO2 and GeO2, the kinds of alkaline earth metal oxides, the concentration of Dy2O3, the heat treatment temperature and the heat treatment time on the structure and properties of germanosilicate optical glasses and oxyfluoride germanosilicate glass ceramics were studied by Raman spectra, absorption-transmission spectra, photoluminescence spectra and X-ray diffraction and son on. The details were listed as following:The germanosilicate optical glasses with different ratio of SiO2 and GeO2 were prepared by melting-annealing method. The [SiO4] tetrahedron, [GeO4] tetrahedron and [SiO4] & [GeO4] polyhedrons exited together in the germanosilicate glass matrix. The luminescence intensity and quenching concentration of Dy3+ions were different when changing the ratio of SiO2 and GeO2. When the ratio of GeO2 and SiO2 was 20 mol%:30 mol% and the concentration of Dy2O3 was 1.00 mol%, the germanosilicate optical glasses had the strongest luminescence intensity. The kinds and contents of alkaline earth metal oxides had no effects on the structure of glass matrix while they had some effects on the luminescence intensity of Dy2O3. The luminescence intensity of Dy2O3 became lower when alkaline earth metal oxides changed as following:MgO→CaO→BaO. The reason was that the smaller of the cation radius, the better of the glass matrix network was improved, leading to the better dispersibility of Dy3+ions.The oxyfluoride germanosilicate glass ceramics were prepared by heat treatment method. The XRD results showed that the Ba3AlF9 microcrystal was formed after heat treatment. The crystal size was smaller than 10 nm. The glass ceramic had high visible-IR transmittance (90%) and had the strongest luminescence intensity after heat treated at 580℃for 4 h. When heat treated at 620℃, the samples became opaque due to coexist of the Ba3AlF9 phase and BaAl2Si2O8 phase. The effects of the concentration of Dy2O3 on the crystallization and luminescence property of samples were studied. The results showed that when the concentration of Dy2O3 is 1.00 mol%, the samples had the strongest luminescence intensity. When the concentration of Dy2O3 increased to 3.00 mol%, there was no Ba3AlF9 microcrystal formed in the samples. The sample heat treated at 580℃for 4 h has the better photoluminescence properties than that of without heat treatment because the Dy3+ions dispersed well with low phonon energy environment of Ba3AlF9 nanocrystallines in the oxyfluoride germanosilicate glass ceramics.