Sulfur speciation and network structural changes in silicate-phosphate glasses

2021 ◽  
Vol 557 ◽  
pp. 120645
Author(s):  
Justyna Sułowska ◽  
Piotr Jeleń ◽  
Zbigniew Olejniczak ◽  
Magdalena Szumera
Keyword(s):  
Structural Changes ◽  
Phosphate Glasses ◽  
Sulfur Speciation

scholarly journals Spectral Investigation of Crystalline (CuHPO4, Cu2P4O12,and Cu2P8O22) and Glassy Copper Phosphates

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Christiane Günther ◽  
Dörte Stachel ◽  
Lydia D. Bogomolova
Keyword(s):  
Absorption Band ◽  
Ir Spectra ◽  
Copper Content ◽  
Structural Changes ◽  
Spectroscopic Properties ◽  
Structure Type ◽  
Phosphate Glasses ◽  
Spectral Investigation ◽  
Copper Phosphate ◽  
Colour Changes

Emerald green crystals of the new composition CuHPO4were synthesized and compared to (copper metaphosphate) Cu2P4O12and (copper ultraphosphate) Cu2P8O22. Various copper ultraphosphate and metaphosphate glasses of different compositions between pure P2O5and Cu2P4O12were melted in crucibles or in evacuated and sealed silica ampoules at 1473 K or 1373 K for 2 hrs. The UV-VIS-spectra and the IR-spectra of all crystals and glasses were measured and compared. The absorption band of Cu2+was resolved into more component Gaussian bands and differentiated between square-pyramidal and octahedrally coordinated copper. These structural changes are responsible for colour changes from green to turquoise. The infrared spectroscopic properties of the copper phosphate glasses differ between metaphosphate and ultraphosphate structures but show similarities between the crystals and the glasses of the same structure type. EPR studies of some of the glasses show different kinds of spectra, with increasing copper content.

Electrodiffusion versus Chemical Diffusion in Alkali Calcium Phosphate Glasses: Implication of Structural Changes

2017 ◽  
Vol 121 (6) ◽  
pp. 3203-3211 ◽  
Author(s):  
Anneli Hein ◽  
Johannes Martin ◽  
Martin Schäfer ◽  
Karl-Michael Weitzel
Keyword(s):  
Calcium Phosphate ◽  
Structural Changes ◽  
Chemical Diffusion ◽  
Phosphate Glasses

Effect of gamma irradiation on X-ray absorption and photoelectron spectroscopy of Nd-doped phosphate glass

2016 ◽  
Vol 23 (6) ◽  
pp. 1424-1432 ◽  
Author(s):  
V. N. Rai ◽  
Parasmani Rajput ◽  
S. N. Jha ◽  
D. Bhattacharyya ◽  
B. N. Raja Shekhar ◽  
...  
Keyword(s):  
Gamma Irradiation ◽  
Photoelectron Spectroscopy ◽  
Glass Matrix ◽  
Structural Changes ◽  
Phosphate Glasses ◽  
White Line ◽  
Edge Structure ◽  
Xps Spectra ◽  
X Ray ◽  
X Ray Absorption

X-ray absorption near-edge structure (XANES) and X-ray photoelectron spectroscopy (XPS) of Nd-doped phosphate glasses have been studied before and after gamma irradiation. The intensity and the location of the white line peak of theL3-edge XANES of Nd are found to be dependent on the ratio O/Nd in the glass matrix. Gamma irradiation changes the elemental concentration of atoms in the glass matrix, which affects the peak intensity of the white line due to changes in the covalence of the chemical bonds with Nd atoms in the glass (structural changes). Sharpening of the Nd 3d5/2peak profile in XPS spectra indicates a deficiency of oxygen in the glasses after gamma irradiation, which is supported by energy-dispersive X-ray spectroscopy measurements. The ratio of non-bridging oxygen to total oxygen in the glass after gamma radiation has been found to be correlated to the concentration of defects in the glass samples, which are responsible for its radiation resistance as well as for its coloration.

Structural model for nitrogen incorporation in phosphate glasses

1991 ◽  
Vol 6 (8) ◽  
pp. 1757-1762 ◽  
Author(s):  
Mary R. Reidmeyer ◽  
Delbert E. Day
Keyword(s):  
Nitrogen Content ◽  
Structural Changes ◽  
Structural Model ◽  
Phosphate Glasses ◽  
Nonbridging Oxygen ◽  
Nitrogen Incorporation ◽  
Structural Types ◽  
Predicted Values ◽  
Oxygen Ratio ◽  
Phosphate Groups

In this paper a model is presented for predicting the structural changes that occur in a metaphosphate glass during nitriding in anhydrous ammonia. Predicted values for the nitrogen content, the mole fraction of phosphate groups, the bridging to nonbridging oxygen ratio, and the ratio of the structural types for nitrogen are compared to the values obtained in earlier experimental work. A plausible correlation is found between the values predicted from this structural model and those observed experimentally. In addition, a maximum nitrogen content (N/P = 0.9) is predicted and the lower nitrogen content normally observed is explained.

scholarly journals Polaronic Conductivity in Iron Phosphate Glasses Containing B2O3

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2505
Author(s):  
Luka Pavić ◽  
Stjepko Fazinić ◽  
Hüseyin Ertap ◽  
Mevlüt Karabulut ◽  
Andrea Moguš-Milanković ◽  
...  
Keyword(s):  
Master Curve ◽  
Structural Changes ◽  
Strong Dependence ◽  
Glass Structure ◽  
Glass Network ◽  
Iron Phosphate ◽  
Phosphate Glasses ◽  
Nominal Composition ◽  
Number Density ◽  
Iron Phosphate Glasses

We report on the electrical properties of glasses with nominal composition xB2O3–(100 − x)[40Fe2O3–60P2O5],x = 2–20, mol.%. The conduction transport in these glasses is polaronic and shows a strong dependence on Fe2O3 content and polaron number density. The changes in DC conductivity are found not to be directly related to B2O3, however structural changes induced by its addition impact frequency-dependent conductivity. All glasses obey Summerfield and Sidebottom procedures of scaling conductivity spectra indicating that the polaronic mechanism does not change with temperature. An attempt to produce a super-master curve revealed that shape of the conductivity dispersion is the same for glasses with up to 15.0 mol.% B2O3 but differs for glass with the highest B2O3 content. This result could be related to the presence of borate units in the glass network. Moreover, the spatial extent of localized polaron motions increases with the decrease of polaron number density, however, this increase shows a larger slope than for previously reported iron phosphate glasses most probably due to the influence of B2O3 on glass structure and formation of polarons. While Summerfield scaling procedure fails, Sidebottom scaling yields a super-master curve, which indicates that polaronic hopping lengths also change with changing polaron number density in these glasses.

Electronic-Ionic Conductivity of Lithium- Vanado- Phosphate Glasses

2017 ◽  
Vol 14 (1) ◽  
pp. 9-14
Author(s):  
Eraiah B
Keyword(s):  
Activation Energy ◽  
Ionic Conductivity ◽  
Structural Changes ◽  
Glass Network ◽  
Phosphate Glasses ◽  
Melt Quenching ◽  
Calculated Activation Energy ◽  
Quenching Method ◽  
Increasing Temperature ◽  
Calculated Activation

The new glassesof glass system x Li 2 O-50 V 2 O 5 -(50-x) P 2 O 5 were prepared by using conventional melt quenching method. The densities of these glasses have been measured by Archimedes method and corresponding molar volumes have also been calculated. The conductivity of these glasses was measured as a function of temperature and composition. The variations of conductivity versus temperature follow Arrehenius type relationship. Conductivity decreases with increasing Li 2 O content and increase with increasing temperature. The calculated activation energy decreases up to 15mol% of Li 2 O, it increases from 15mol% to 30 mol% of Li 2 O and again it suddenly drops at 40 mol% of Li 2 O. This may be due to structural changes in glass network and these glasses exhibit both electronic and ionic conductivity.

STRUCTURAL INVESTIGATIONS ON CALCIUM-SILICA-PHOSPHATE GLASSES

2002 ◽  
Vol 16 (20) ◽  
pp. 761-767 ◽  
Author(s):  
V. SIMON ◽  
S. SIMON ◽  
D. ENIU
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Glass Matrix ◽  
Structural Changes ◽  
Structural Evolution ◽  
Phosphate Glasses ◽  
Structural Investigations ◽  
Intermediate Range Order ◽  
Ionic Field

Glass transition and crystallization temperatures established from differential thermal analysis (DTA), density, molar volume and ionic field strength changes induced by the addition of Fe 2 O 3 to the CaO-P 2 O 5- SiO 2 glass matrix, are correlated in order to understand the structural role of iron oxide in the investigated glasses and to discover the structural evolution of the samples as a function of composition. The compactness degree in calcium-silica-phosphate glasses increases when Fe 2 O 3 is added. The results suggest structural changes characteristic of intermediate range order.

Fine Structural Changes in the Microvasculature of the Mouse Pinna: Aging and Radiation Injury

1974 ◽  
Vol 32 ◽  
pp. 54-55
Author(s):  
S. Phyllis Steamer ◽  
Rosemarie L. Devine
Keyword(s):  
Structural Changes ◽  
Radiation Treatment ◽  
Arterial Stenosis ◽  
Ultrastructural Changes ◽  
Vascular Effects ◽  
Microvascular Changes ◽  
Surrounding Connective Tissue ◽  
Fission Neutrons ◽  
Total Body

The importance of radiation damage to the skin and its vasculature was recognized by the early radiologists. In more recent studies, vascular effects were shown to involve the endothelium as well as the surrounding connective tissue. Microvascular changes in the mouse pinna were studied in vivo and recorded photographically over a period of 12-18 months. Radiation treatment at 110 days of age was total body exposure to either 240 rad fission neutrons or 855 rad 60Co gamma rays. After in vivo observations in control and irradiated mice, animals were sacrificed for examination of changes in vascular fine structure. Vessels were selected from regions of specific interest that had been identified on photomicrographs. Prominent ultrastructural changes can be attributed to aging as well as to radiation treatment. Of principal concern were determinations of ultrastructural changes associated with venous dilatations, segmental arterial stenosis and tortuosities of both veins and arteries, effects that had been identified on the basis of light microscopic observations. Tortuosities and irregularly dilated vein segments were related to both aging and radiation changes but arterial stenosis was observed only in irradiated animals.

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