Browsing by Author "Lączka, Maria"

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    Influence of aluminium and neodymium additions on the structural relaxation of silica glasses - Raman investigations
    (Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1988) Lączka, Maria; Czerwosz, Elżbieta
    Raman spectra of silica glasses obtained from melted rock crystal without additions and of glasses doped with aluminium and neodymium were examined. The relative intensity of the 606 cm^-1 band in Raman spectra was evaluated. The occurrence of this band is due to the presence of defects in the glass structure. The time required by the 606 cm^-1 band to attain the equilibrium intensity at 1000 °C has been defined as the relaxation time of the silica glass structure under the given conditions of heat treatment. It has been found that additions in silica glass in the form of Al3+ and Nd3+ ions do not affect the value of the equilibrium intensity of the 606 cm^-1 band and thus, they do not affect the equilibrium concentration of the defects which give rise to this band. However, the additions have a distinct effect on the length of the relaxation time of the glass structure. Neodymium, when occurring as a single addition of silica glass, reduces the relaxation time, whereas aluminium clearly makes the structure relaxation difficult. Glass doped both with aluminium and neodymium (Al2O3/Nd2O3 = 4) behaves similarly as glass doped with aluminium only. The role of additions in the structure of silica glass was discussed on the basis of the investigation results.
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    Synthesis, structure and certain properties of melted and sol-gel glasses in the SiO2 and Al2O3-SiO2 systems
    (Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1989) Lączka, Maria; Beier, Wolfram; Stoch, Leszek
    SiO2 and SiO2-Al2O3 glasses containing 1 to 10 mol% Al2O3 were examined. The glasses were obtained by electrical melting of quartz and by the sol-gel method from alcoholate solutions. Using the gel glasses thin layers on soda-lime-silica glass were obtained. These layers offer good protection of glass against the corrosive action of water. DTA investigations of gel glasses were carried out showing the influence of Al2O3 in the processes of water release and combustion of organic matter. Measurements of the IR spectra and the ESCA spectra were performed and the radial distrubution function (RDF) of melted and gel glasses examined. The crystallization kinetics of these glasses was also investigated. On the basis of the obtained results the similarities and differences in the structures of glasses obtained by melting and by thermal treatment of gels are indicated.
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    Synthesis, structure and electron spectra of fused quartz doped with titanium, cerium and neodymium
    (Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1988) Lączka, Maria; Stoch, Leszek
    Vitreous silica doped with titanium, cerium or neodymium having specific optical properties was produced by fusing rock crystal or quartz minerals in an electrical vacuum furnace. The dissolution of titanium, cerium and neodymium compound s in vitreous sliica is facilitated by aluminum, either present in the raw material or introduced for this purpose in the form of added chemical compounds. The role of the doping ions in the structure was interpreted on the basis of their electron spectra.