Soda Lime Aluminosilicate Glasses Research Articles

Structural analysis and visible light-activated photocatalytic activity of iron-containing soda lime aluminosilicate glass

A relationship between structure and visible light-activated photocatalytic activity of iron-containing soda lime aluminosilicate (15Na2O⋅15CaO⋅40Fe2O3⋅xAl2O3⋅(30−x)SiO2) glass (xNCFAS) was investigated by means of 57Fe-Mössbauer spectroscopy, X-ray diffractometry (XRD) and UV–visible light absorption spectroscopy (UV–VIS). The 57Fe-Mössbauer spectrum of 11NCFAS glass measured after heat-treatment at 1000°C for 100min was composed of a paramagnetic doublet due to FeIII(Td) and two magnetic sextets due to regular hematite (α-Fe2O3) and hematite with larger internal magnetic field. X-ray diffraction patterns of heat-treated xNCFAS samples resulted in decrease of α-Fe2O3 and increase of Ca2Fe22O33 or CaFe2O4 with alumina content. A quick decrease in methylene blue (MB) concentration from 15.6 to 4.7μmolL−1 was observed in the photocatalytic reaction test with 40mg of heat-treated 11NCFAS glass under visible light-exposure. The largest first-order rate constant of MB decomposition (k) was estimated to be 9.26×10−3min−1. Tauc’s plot yielded a band gap energy (Eg) of 1.88eV for heat-treated 11NCFAS glass, which is smaller than previously reported Eg of 2.2eV for α-Fe2O3. These results prove that addition of Al2O3 into iron-containing soda lime silicate glass is favorable for the preparation of improved visible light-photocatalyst with ‘ubiquitous’ elements.

IR Practical Extinction Coefficients of Water in Alkali Lime Silicate Glasses Determined by Nuclear Reaction Analysis

Infrared spectroscopy (IR) is widely used to determine the water concentration in glasses, whereas determination of the IR practical extinction coefficient is necessary to deduce the absolute water concentration of glasses on the basis of Beer–Lambert law. From the nuclear reaction analysis data, the IR practical extinction coefficients of water were successfully determined for the alkali lime silicate glasses with different levels of sodium/potassium cation (Na/K) ratio. The two‐band method is well‐known to be useful for the determination of the water concentration in some alkali lime silicate glasses. It is proved here that the two‐band method is not applicable to the variety of composition for alkali lime silicate and soda lime aluminosilicate glasses, whereas it is valid for the similar composition of soda lime silicate glasses [SLS: Composition (in mol%) 16Na2O·10CaO·74SiO2]. The single‐band procedure with the IR practical extinction coefficient is crucial for the determination of the precise water concentration in the wide variety of glass composition although the determination of the IR practical extinction coefficient is troublesome. It also appears that the ion radius of alkali affects the IR practical extinction coefficient and the chemical state of OH group in glasses.

Practical IR extinction coefficients of water in soda lime aluminosilicate glasses determined by nuclear reaction analysis

Abstract Infrared absorption spectroscopy (IR) is widely used to determine the water content in glasses, whereas determination of the practical extinction coefficient is necessary to deduce the absolute water concentration of glasses on the basis of Beer–Lambert law. On the basis of the nuclear reaction analysis (NRA) data, the IR practical extinction coefficient of water was successfully determined for the glasses with different levels of Al contents. Whereas the two-band method is well known to determine the water concentration in alkali lime silica glasses, we show that the single-band procedure with a practical absorption coefficient is suitable for the determination of the water concentration in soda lime aluminosilicate glasses containing substantial amounts of Al content. A good correlation is confirmed between the non bridging oxygens/tetrahedral cations (NBO/T) ratio and the practical extinction coefficient of water in soda lime aluminosilicate glasses with identical network-modifying cations.

A method of surface strengthening of soda lime aluminosilicate glasses by Li and Al ion vapour treatment

A method of strength enhancement of soda lime silica based container glass compositions is described for the first time that employs simplified vapour treatment protocols of Li and Al ion diffusion from gas phase sources of LiBr and AlBr3 into Float, soda-lime-silica and commercial compositions with or without added Al2O3. An overall strength of 33-121 % without discernible loss of transparency was achieved. LiBr treatment at 585 oC produced strength values of about 400 MPa for the base and the alumina modified glasses. AlBr3 exposure resulted in an increase of 49-95 % to 355 MPa for only 30 minute treatment, but proportionally lowers for shorter times. No appreciable reduction in strength occurred on follow-up heat treatments. Consecutive AlBr3 and LiBr treatment was highly effective in 121 % improvement in strength for 30 and 10 minute exposure, respectively. Presence of Al ion in the bulk and Li diffusion is suggested to form low TCE phases, culminating in the observed strength increase.

Optical and spectroscopic properties of soda lime alumino-silicate glasses doped with erbium and silver

Spectroscopic properties of Ag/Er co-doped soda lime silicate glasses have been studied with the aim of assessing the effective role of silver as a sensitizer for erbium. Changes in spectroscopic properties of Er 3+ as a function of silver addition to the base composition have been measured. Transmission electron microscopy (TEM), absorption as well as photoluminescence measurements in the visible and infrared spectral region, particularly 4I 13/2 → 4I 15/2 transition of the Er 3+ ion were performed; excitation wavelengths in the range from 325 to 808 nm were used. Enhancement of the Er 3+ luminescence at 1.54 μm was observed when Ag was added.

Integrated optical amplifiers and microspherical lasers based on erbium-doped oxide glasses

Abstract Er 3+ -doped glasses have been a subject of great interest in the recent years for their application in the areas of guided wave optical amplifiers and lasers. Oxide–glass matrices, in particular, offer the advantage of relatively simple fabrication processes—both for bulk glasses and optical fibers—and have demonstrated quite good properties in the 1.5 μm wavelength band. Here we present some results we have obtained in the development of different silica-based glasses and in their application to the production of integrated optical amplifiers and microspherical lasers. As to the former application, two classes of silica glasses have been produced and investigated, namely a melted soda-lime–alumino-silicate glass and a sol–gel silica–hafnia glass. Both of them exhibit a wide emission bandwidth and seem quite promising for broadband optical amplifiers. We also demonstrated low-threshold microlasers, based on whispering gallery mode spherical resonators, fabricated in different oxide glasses.

Ca and Na environments in Na 2O–CaO–Al 2O 3–SiO 2 glasses: influence of cation mixing and cation-network interactions

X-ray absorption spectroscopy at Ca and Na K-edges and Molecular Dynamics (MD) simulations are used to investigate the Ca and Na environment in soda lime aluminosilicate glasses. Both X-ray Absorption Near Edge Structure (XANES) spectra and MD calculations indicate a coordination number of about 7 for Ca and 6 for Na, in a distorted polyhedron. Ca and Na XANES spectra are poorly affected either by the Si/Al substitution or the Ca/Na substitution while MD simulations present some variations in the cationic environment. We show an affinity for non-bridging oxygens (NBOs) to be connected with Ca rather than Na. Evidence of Ca–Na mixing is shown by the MD models and there is a tendency toward forming more regions enriched in (Ca, NBOs) for CaO-rich aluminosilicate glasses. Variations in the cationic mobility upon the Na/Ca substitution are correlated with the observed structural modifications.

The crystallization of indium containing semiconductive phases from a soda–lime–aluminosilicate glass

Glasses in the system Na 2O/CaO/Al 2O 3/In 2O 3/As 2O 3/SiO 2 were thermally treated at temperatures in the range 650–1000°C. In glasses containing ⩾10 mol% Al 2O 3, this led to the crystallization of nanocrystalline In 2O 3. At 650°C, a mean crystallite size of 7 nm was determined by X-ray diffraction (XRD)-line broadening. In glasses with lower Al 2O 3-concentration, In 2O 3-crystallization did not occur. Thermal treatment under strongly reducing conditions (H 2/N 2 gas mixture) resulted in the formation of nanocrystalline InAs. Both materials synthesized are potentially useful for non-linear optics.

Hydration of soda-lime silicate glass, effect of alumina

Profiles of the elements in the surface of hydrated soda-lime silicate and soda-lime alumino-silicate glasses were measured with a resonant nuclear reaction (hydrogen) and Rutherford backscattering. The profiles were consistent with interdiffusion of sodium and hydrogen-bearing ions. Interdiffusion in the glass without alumina was faster, presumably because it had a transformed surface layer. A small amount of preferential leaching of calcium was detected in this glass.