Gan Fuxi

Low temperature synthesis of ZrO2TiO2SiO2 glasses from Zr(NO3)4 · 5H2O, Si(OC2H5)4 and Ti(OC4H9)4 by the sol-gel method

Abstract ZrO 2 - and/or TiO 2 -containing silicate glasses have been attracting more and more scientists and technologists due to their low thermal expansion and excellent resistance to alkali corrosion. But it is difficult to make these glasses by the conventional melting method because of their extraordinarily high melting temperatures. In the present work, however, glasses in the ZrO 2 ue5f8TiO 2 ue5f8SiO 2 systems have been successfully synthesized by the sol-gel route using Zr(NO 3 ) 4 · 5H 2 O, Si(OC 2 H 5 ) 4 and Ti(C 4 H 9 ) 4 as starting materials. Transparent glass pieces were obtained containing 20 mol.% TiO 2 and up to 30 mol.% ZrO 2 . Detailed studies were carried out on the whole synthesis process including hydrolysis, polymerization, gelling and conversion from gel to glass. Research results on the viscosity evolution of the reaction systems showed that environmental humidity and catalyst had important effects on the gelling process. During heat treatment, the colour of the dry gels gradually changed and DTA data indicated that at about 650°C the conversion from gel to glass would be completed. The information about the structural variation of the gels during heat treatment has been obtained by means of X-ray diffraction, infrared spectroscopy and the results suggest the different function of Zr 4+ ions from Ti 4+ ions in this kind of glass, i.e. Ti 4+ ions act as network formers, while Zr 4+ ions act as network modifiers.

Luminescence of Cu+ ions in phosphate glass

Abstract Time-resolved fluorescence and lifetime measurements of Cu+ ions in phosphate glass with different copper concentrations have been performed at room temperature and 77 K. The experimental results are explained by energy transfer.

Spectroscopy of transition metal ions in inorganic glasses

Abstract Transition metal (TM) ions have been used as colouring agents in the glass industry for a long time. Recently, great attention has been paid to the TM ion doped glasses for the development of new lasers or luminescence materials. The absorption spectra of TM ions in different kinds of glasses have been studied extensively, but little work has been done for fluorescence and relaxation spectra. In this paper emphasis is laid on analysing the influence of chemical bond characteristics of the base glass on the spectra and the site structure of transition metal ions in glasses. Recent experimental results about the luminescence characteristics of low valence ions (such as Ti 3+ , Cr 3+ , V 2+ , Mn 2+ , Cu + , Mo 3+ ) in glasses are also reported.

Structure and Raman spectra of glasses containing several glass-forming oxides and no glass-modifying oxide

Abstract Binary glasses containing no modifying oxides, such as SiO2ue5f8GeO2, SiO2ue5f8B2O3, SiO2ue5f8P2O5, GeO2ue5f8B2O3, Al2O3ue5f8P2O5 and ternary glasses SiO2ue5f8GeO2ue5f8P2O5, Al2O3ue5f8B2O3ue5f8P2O5, B2O3ue5f8SiO2ue5f8P2O5, Al2O3ue5f8ZrO2ue5f8P2O5 have been prepared by melting and CVD methods. The Raman spectra have also been measured. Structural characteristics of SiO2, GeO2, B2O3, P2O5 in different glass systems are analysed. There exist coordination number changes in B2O3- and GeO2-containing glasses and linkage changes between tetrahedra (SiO4) and (PO4) in SiO2 and P2O5 containing glasses. The structure of Al2O3 containing glasses is homogeneous and the structure of B2O3 containing glasses is inhomogeneous. These experimental results are in coincidence with the X-ray small angle scattering analysis.

Study on devitrification and properties of GeAsS glass system

Abstract The devitrification and properties of Geue5f8Asue5f8S glass system have been studied. The morphology and composition of the phase separation region in this glass system have been determined. The infrared absorption spectra, laser Raman spectra and a series of physical properties of glasses have been measured also. The relationship between phase separation and structural units, composition and properties are discussed.

Glass formation of several semiconductors and alloys by laser irradiation

Abstract Several samples of semiconductors (InSb and InSbTe) and alloys (FeBC, FeNiPBC and AlSi) were irradiated by a high-power CW CO 2 laser and pulsed YAG laser beams. The surface morphology of the samples was examined by a scanning electron-microscope (SEM). The reflection electron diffraction patterns were recorded by using a transmission electron microscope (TEM). The critical cooling rate for glass formation of different samples has been determined. Characteristics of the glass formation process are discussed.

Luminescence of Er3+ ion in noncrystalline fluoride

Some luminescence of Er3+ ions in the fluoride glasses are studied. One of the cross-relaxations of Er3+ ions is between 11/2H2-9/2I4 and 15/2I4-13/2I4. The Er3+-Er3+ ions interaction causing the cross-relaxation in the fluoride glasses is an electric dipole-dipole interaction.

Time-resolved fluorescence spectra of titanium-containing fluorophosphate glass

Abstract The visible luminescence due to Ti 3+ ions in titanium-containing fluorophosphate glass has been observed with UV excitation. Time-resolved fluorescence and lifetime measurements have also been performed at room and low temperature, respectively.

Raman spectra of LiYF4 crystal

The polarized Raman spectra of lithium yttrium fluoride crystal for the incident light along different axes are presented and the vibrational modes of the crystal structure are discussed.

Nonlinear refractive coefficient and self-focusing damage in glasses

We have investigated some nonlinear optical effects in a series of optical glasses and laser glasses. Using different methods, we have measured the nonlinear refractive coefficient of these glasses. We have analyzed the possible mechanisms resulting in refractive index change in glass and calculated their nonlinear refractive coefficients. We have also discussed the dependence of laser-induced damage and thermo-optical blooming on nonlinear refractive coefficients.