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The influence of the spheroidization process occurring in 1.0 mol.% Nd2O3 doped Li2O–Al2O3–SiO2 (LAS) glass in a high-temperature plasma flow on the properties of glass crystallization was investigated. The resulting 32 – 64 μm microspheres are characterized by a significantly higher glass transition temperature Tg compared to that of the original glass, which could be associated with both a change in the chemical composition on spheroidization and a fundamentally different thermal history of the microspheres and glass. In spite of the moderation of the crystallization kinetics, in microspheres as well as in the original glass, under the influence of heat treatment, a glass-ceramic structure is formed based on â-eucryptite-like solid solutions LixAlxSi1–xO2, indicating the possibility of obtaining microspheres with glass-ceramic structure as well as varying their linear thermal expansion coefficient near zero values. [ABSTRACT FROM AUTHOR]

The crystallisation kinetics and effects of doping on Bi2Sr2CaCu2Oδ (BSCCO) glass ceramic system with 0.0%, 0.1%, 0.3% and 0.5% PbSe were investigated in this study. Differential thermal analysis (DTA) was used to investigate the effects of PbSe doping on glass transition, nucleation and crystallisation temperature of glass were investigated. The DTA results were analysed using the Ozawa, Augis–Bennett, Takhor and Kissinger equations for nucleation kinetics to determine the activation energies and Avrami parameters. Thermogravimetric analysis revealed that the amount of oxidation in the structure increased with increasing PbSe-doping concentration. [ABSTRACT FROM AUTHOR]

The results of the synthesis of lanthanum borate glasses modified with highly polarizable cations (Nb, Ti, Zr, Ta) are described, their crystallization properties were studied, and their structural features were investigated by means of IR spectroscopy. It was determined that glass blanks with refractive index > 1.8 can be obtained in the composition range 25La2O3–xMnOm–(75 – x)B2O3 (M = Nb, Ta, Ti, Zr, x = 5 – 25 mol.%). It is proposed that a network of large polyhedra of the modifying cation, which are bound at the vertices, is formed in addition to the borate network, thereby allowing the melt to retain its glass-forming ability. [ABSTRACT FROM AUTHOR]

The effect of added Al2O3, introduced by the substitution method, on the crystallization and spectral-luminescent properties of gallium germanosilicate glasses with γ-Ga2O3:Ni2+ nanocrystals was investigated. It was found that the Ni2+-luminescence efficiency increased on account of both an increase in the degree of crystallinity of glass with Al2O3 and an increase in the strength of the crystal field around the Ni2+ ions on account of Al3+ incorporation into the structure of the precipitated nanocrystals. [ABSTRACT FROM AUTHOR]

The effect of added Al2O3, introduced by the substitution method, on the crystallization and spectral-luminescent properties of gallium germanosilicate glasses with γ-Ga2O3:Ni2+ nanocrystals was investigated. It was found that the Ni2+-luminescence efficiency increased on account of both an increase in the degree of crystallinity of glass with Al2O3 and an increase in the strength of the crystal field around the Ni2+ ions on account of Al3+ incorporation into the structure of the precipitated nanocrystals. [ABSTRACT FROM AUTHOR]

The influence of calcium fluoride, zinc oxide, and boron oxide as modifying additives on the melting and crystallization properties of strontium aluminosilicate glasses is examined. The influence of the type and amount of the modifying additive on the homogeneity of the molten glass and the quality of glass castings was evaluated visually. Bulk crystallization and XRD were used to study the effect of additives on the formation of the crystalline structure of the glasses. [ABSTRACT FROM AUTHOR]

The particulars of the effect of focused femtosecond laser pulses on antimony silicate glass with the composition 25Sb2O3∙75SiO2 % (molar content) in thermal and athermal regimes were studied. It was found that in contrast to quartz, alkali silicate, and some borosilicate glasses the birefringence of the form characteristic for the formation of nanogratings does not arise in the laser-modified zones of the studied glass. Weak birefringence with slow axis parallel to the polarization plane of the writing laser beam, accompanied by precipitation of crystalline phases, seemingly including the cubic modification of Sb2O3, arises in the modified zones under irradiation by 106 pulses with energy > 100 nJ and repetition frequency 10 and 200 kHz. [ABSTRACT FROM AUTHOR]

The possibility of glass formation in the four-component system La2O3–Al2O3–B2O3–SiO2 with La2O3 molar content 27% was studied. The ratios of the components for which the glasses are most stable with respect for amorphous phase separation and crystallization were determined. The composition range bounded by the limit values of the molar content of the components — 7 – 30 SiO2, 8 – 25 Al2O3, and 32 – 50 B2O3 — makes it possible to obtain glass with refractive index nD to 1.74, dispersion coefficient vD to 57, and density ≤ 4.15 g/cm3. The manufacturability of these glasses creates the prerequisites for developing materials with different combinations of optical constants by modifying the matrix with a wide range of dopants. [ABSTRACT FROM AUTHOR]

The results of synchronous thermal, x-ray phase, electronic paramagnetic resonance, and optical spectroscopy analyses of the physical-chemical and structural processes occurring during the heat treatment of strontium-aluminosilicate glass are presented. The dependence of structure-formation processes on the chemical composition of the glass is studied. [ABSTRACT FROM AUTHOR]

The results of experimental studies of the physical-chemical parameters of basaltic glass synthesized by reduction melting of batch from dolerite and limestone and differing by the total content of bi- and trivalent iron are presented. It is shown that as the iron oxide content in the melt decreases the capability of the melt to form continuous fibers decreases because the structure of the glass breaks down and the fibers become weaker. [ABSTRACT FROM AUTHOR]

Glass formation, crystallizability, physical-chemical properties, and spectral characteristics of GeO-TeO-BO-PbO glasses were studied. The structural properties of the glasses were investigated and the coordination transitions of boron and germanium ions in the glass structure were found. A nonlinear dependence of the physical-chemical properties of the glasses on their composition and structure was found and interpreted as a manifestation of 'borate and germanate' anomalies in the glasses. The optical absorption spectra of the glasses were found to be characterized by a steep fundamental absorption edge at the boundary of the visible and UV regions of the spectrum, which makes it possible to recommend the glasses for use as light filters cutting off the UV region. [ABSTRACT FROM AUTHOR]

Glasses with the composition (in moles) 2BiO, 3GeO have been obtained. They have different color and electric properties. This is due to the different concentration of bismuth ions with degree of oxidation different from +3. The characteristic temperatures of these glasses have been determined, and on the basis of these temperatures heat-treatment regimes were chosen in order to obtain a transparent glass ceramic. The effect of the glassmaking regimes on the glass crystallization process is established. Some physical-chemical properties of the glass ceramic obtained have been investigated. [ABSTRACT FROM AUTHOR]

The features of the effect of the composition and structure of glasses of the systems NaO - CaO - BO - SiO and NaO - CaO - BO - AlO - SiO on the temperature curve of the viscosity in the 10 - 10 Pa · sec range were established. The important effect of phase separation processes-liquation and crystallization-on the viscosity indexes in the temperature region of the transition from the plastic to the liquid state was demonstrated. [ABSTRACT FROM AUTHOR]

The mechanism of microliquation in RO - RO - TiO- PO- RO- SiO glasses is established. In these glasses, after heat treatment drop liquation leads to finely disperse volume sitallization of the crystalline component of the glass undergoing liquation. The formation of secondary spherical nonuniformities about 1 nm in size with drop-like formations intensifies the crystallization of glass after heat-treatment. [ABSTRACT FROM AUTHOR]

Facing and decorative glass crystal materials were developed from mineral feedstock and technogenic wastes. The effect of the components present in the mineral feedstock in liquation and crystallization of the glasses was investigated. The materials obtained can be used in construction for facing walls. [ABSTRACT FROM AUTHOR]

The process of glass solidification is analyzed in the context of the fundamental principles of physicochemical kinetics. The concept of the emergence of “solidification seeds”, formation of “solidification layers” and their migration into the glass volume are discussed. It is demonstrated that the level of diathermancy of tinted glasses can characterize the force of the interaction between the colorant complexes and the main silicon-oxygen elements in glass and, consequently, can influence viscosity variation in solidifying. The proposed theoretical principles agree well with experimental and industrial data. [ABSTRACT FROM AUTHOR]

A large number of publications addressing the solidification of glass in molding has been systematized. Different aspects of the effect of the basic composition of glass, diathermancy, time and structural factors on solidification processes are discussed. The workability of glasses and the main conditions for mechanized formation of glass articles are considered as well. [ABSTRACT FROM AUTHOR]

IR spectroscopy and Raman scattering have been used to study the structure of multicomponent silicate glass with phosphorus oxide addition, simulating the commercial compositions of container glass and sheet float-glass. It is established that P2O5 addition gives a micro-nonuniform structure consisting of silicon oxide anionic groupings, with different degrees of connectedness, and orthophosphate groupings. Such nonuniformity promotes subsequent liquation and crystallization of multicomponent glasses containing phosphorus. [ABSTRACT FROM AUTHOR]

Glass-formation in potassium-lithium-aluminosilicate system is studied. The effect of tin oxide on the crystallization properties of K2O–Li2O–Al2O3 – SiO2 glasses is studied. The crystallization properties of transparent and opacified glasses are compared. The phase composition of the products of their crystallization is studied. [ABSTRACT FROM AUTHOR]

The capillary force and crystallization strength of glass batch components are studied moistening the batch with solvents of sodium carbonate, sodium sulfate, and other components. The obtained data can be used for solving problems related to moistening glass batches. [ABSTRACT FROM AUTHOR]

The crystallization capacity of glasses based on the system ZnB2O4 – NaPO3 is investigated. The results of differential-thermal analysis, polythermic analysis, and x-ray phase analysis are described, making it possible to identify the crystallization intervals and the dependence of crystallization on the temperature-time factor. [ABSTRACT FROM AUTHOR]

The possibility of using self-propagating crystallization accompanied by the propagation of the crystallization heat wave front in the transition of foam silica produced on the basis of compositions in the system CaO – MgO – Al2O3 – SiO2 by the reducing melting method with melt separation and subsequent cooling of the silicate component under a thermal shock from the x-ray-amorphous state to the crystalline state is studied. The characteristics of the thermal wave are identified, the dependence of the velocity of propagation of the thermal wave on the dispersion of the foam silicate and molding pressure is established. [ABSTRACT FROM AUTHOR]