الفهرس 
Aim of the WorkOnly 14 pages are availabe for public view
 |  | from | 199 |  |  |
| | | from | 199 | | |
Abstract
SLS glasses are attractive materials for the fabrication of low cost integrated optical amplifiers and other commercial tableware and sheet glasses. Infrared (IR) absorption spectra of some prepared undoped and transition metals doped soda-lime-silicate glasses have been studied in the region of 4000-400 cm-1. IR spectra were analyzed to determine and differentiate the various vibrational modes by applying the deconvolution method to the IR spectra. Although the first sight reveals close similarity between the different transition metals (TM’s) - doped samples, but careful inspection indicates some minor differences depending on the type of TM ions. These observed data are correlated with the similarity of the 3d orbital in the neutral atoms and when the atoms are ionized, the 3d orbital becomes more stable than the 4s orbital. Fourier transform infrared (FTIR) spectroscopy was used to monitor and confirm the proposed corrosion mechanisms on the surfaces of some prepared undoped Na2O-CaO-SiO2 (SLS) glass together with samples doped with one of the first 3d-transition metal oxides (TMO) (TiO2→CuO) exposed to an aqueous solution for fixed time (1hr). The traditional proposed mechanism of silicate glass corrosion through ion exchange is analyzed in correlation with infrared reflectance vibrational spectral analysis that could confirm the suggested mechanism. The effects of 3d transition metal oxides are followed and interpreted. UV/Vis. optical analysis for as prepared undoped and doped transition metal oxide glasses were used to shed more light on the structural modification that occur due to different dopants. The UV-Vis. Spectral analysis for undoped glass shows induced absorption bands at 320 nm which are assumed to be correlated with impurities in base host glass and dopant transition metal ion doped glasses. The positions of the bands in each doped samples was found to be different due to the combined effect of induced defects from the host base glass or the transition metal added. Mechanical properties of prepared glass (density and Vicker’s microhardness test) were made and results leads to a linear correlation between density and hardness which found to be in general increasing behavior with addition of transition metal. Addition of lead in silicate glass reduces the melting point and network connectivity, but increases the density, refractive index, chemical corrosion, electrical conductivity, and radiation attenuation coefficient of X- and gamma-rays. Lead silicate glass (LSG) is significantly used in many different areas from radiation protection, video-screen manufacturing and electrode glass production to ophthalmic biotechnology. The study of dissolution of LSG in both environmental and industrial solutions is of considerable importance. Lead silicate glasses (LSG) of the basic composition PbO 75%, SiO2 25% together with samples containing (~0.1%) of transition 3d metal oxides (Ti→Cu) were prepared. Fourier transform infrared (FTIR) spectroscopy was used to monitor and confirm the proposed corrosion mechanisms on the surfaces of some prepared undoped (LSG) glass together with samples doped with one of the first 3d-transition metal oxides (TMO) (TiO2→CuO) exposed to an aqueous solution for fixed time (1hr). The traditional proposed mechanism of silicate glass corrosion through ion exchange is analyzed in correlation with infrared reflectance vibrational spectral analysis that could confirm the suggested mechanism. The effects of 3d- transition metal oxides are followed and interpreted. UV/Vis. optical analysis for as prepared and after successive gamma irradiated samples were used to shed more light on the structural modification that occur due to different dopants and different irradiation doses. The UV-Vis. spectral analysis for undoped glass shows induced absorption bands at 205-400 nm which are assumed to be correlated with base host glass and dopant transition metal ion doped glasses and dose of irradiation. The positions of the bands are observed to change slightly by gamma irradiation due to the combined effect of induced defects from the host base glass or the transition metal added. Gamma irradiation is observed to cause a decrease in the intensities of the IR absorption bands of the prepared samples accompanied by losing sharpness. These features are related to more amorphicity or disorder by irradiation or to the possible changes in bond angle or bond length in the Building group arrangement.