Dispersion, ionic bonding and vibrational shifts in phospho-aluminosilicate glasses.

Understanding the relationships between structure and properties of aluminosilicate glasses is of interest in magmatic studies as well as for glass applications as mechanical or optical components. Glass properties may be tailored by the incorporation of additional elements, and here we studied the effect of phosphate incorporation on refractive index and the degree of ionic bonding in aluminosilicate glasses. The studied glasses in the system SiO-AlO-NaO-PO had a metaluminous composition (Al:Na = 1) with the content of SiO ranging from 50 to 70 mol% and of PO from 0 to 7.

Zinc borate glasses: properties, structure and modelling of the composition-dependence of borate speciation.

The short-range order of binary zinc borate glasses, ZnO-(1-)BO, has been quantitatively described as a function of ZnO content over the entire glass forming range for the first time, to the best of our knowledge. Multiple spectroscopic techniques (B NMR, Raman, infrared) reveal detailed structural information regarding borate speciation and network connectivity, and a new model for quantifying the molar fractions of short-range order units is proposed. A consistent thermal history dependence for the fraction of tetrahedral boron () is well accounted for by the proposed model.

Pressure-Induced Structural Transformations and Electronic Transitions in TeO Glass by Raman Spectroscopy.

TeO glass has been studied by Raman spectroscopy up to the record pressure of 70 GPa. The boson peak frequency ω exhibits a decrease of the ∂ω/∂ slope at 5-6 GPa and saturates above 30 GPa with a practically constant value up to 70 GPa. Experiment and theory indicate that pressures up to 20 GPa induce the transformation of single Te-O-Te bridges to double Te-O-Te bridges, leading to a more compact structure, while Raman activity developing at higher pressures around 580 cm signals the increase of Te coordination from 4- to 6-fold.

Influence of Phosphate on Network Connectivity and Glass Transition in Highly Polymerized Aluminosilicate Glasses.

Melt-derived metaluminous (Al/Na = 1) aluminosilicate glasses in the system SiO-AlO-NaO-PO were prepared with PO and SiO contents varying from 0 to 7.5 and 50 to 70 mol %, respectively. The glass structure was investigated by X-ray absorption near edge structure, far- and medium-infrared, and polarized Raman spectroscopic techniques.

Short-range structure, the role of bismuth and property-structure correlations in bismuth borate glasses.

Bismuth-containing borate glasses, xBi2O3-(1 - x)B2O3, were synthesized in the broad composition range 0.20 ≤ x ≤ 0.80 by melting in Pt crucibles and splat-quenching between two metal blocks.