The structure of alkali germanophosphate glasses by Raman spectroscopy

Henderson, Grant S.; Amos, Richard T.

doi:10.1016/s0022-3093(03)00478-2

Cited by 96 publications

(95 citation statements)

References 28 publications

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“…8,23 The residual X−O−Y network vibrations in the range of 200−600 cm −1 are hard to attribute to certain species but pronounced changes can be documented here as well. For x = 0.2 a pronounced signal at 418 cm −1 can be observed indicating the presence of four-membered germanate rings.…”

Section: −5mentioning

confidence: 76%

Mixed Network Former Effects in Oxide Glasses: Spectroscopic Studies in the System (M₂O)_1/3[(Ge₂O₄)_x(P₂O₅)_1–x]_2/3

Behrends

Eckert

2014

J. Phys. Chem. C

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The structure of mixed-network former glasses in the system (M2O)0.33[(Ge2O4) x (P2O5)1–x ]0.67.(M = Na, K) has been studied by 31P and 23Na high-resolution and dipolar solid state nuclear magnetic resonance (NMR) techniques, O-1s X-ray photoelectron spectroscopy, and Raman spectroscopy. Using an iterative fitting procedure, a quantitative structural model has been developed that is consistent with all of the experimental data and which provides a detailed description of network connectivities, network modification processes, and spatial cation distributions. Formation of heteroatomic P–O–Ge linkages is generally preferred over homoatomic P–O–P and Ge–O–Ge linkages, as shown by a detailed comparison with a random linkage model. An exception occurs in glasses with low germanium contents (x = 0.2) where a pronounced nonlinear dependence of the glass transition temperature on x can be related to a cross-linking of the sodium ultraphosphate network by fully polymerized germanium species, possibly including also 5- and 6-fold coordination states. At higher x values, the Ge component is modified as well, however, the fraction of anionic nonbridging oxygen atoms bound to germanium is always lower than expected for proportional modifier sharing between both network formers. Rather, the phosphate component is preferentially modified by the cations, leading to the formation of P(1) units at high x values. Consequently, the local coordination of the cations is dominated by phosphorus, as is clearly evident from the 23Na{31P} rotational echo double resonance (REDOR) results. This preferred association, combined with the formation of P(1) units, results in partially clustered cation distributions, which can be detected by 23Na spin echo decay spectroscopy. Finally, the joint interpretation of all of the data from NMR, Raman, XPS, and thermal analysis measurements offers indirect evidence for the formation of higher germanium coordination states in this glass system.

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Section: −5mentioning

confidence: 76%

Mixed Network Former Effects in Oxide Glasses: Spectroscopic Studies in the System (M₂O)_1/3[(Ge₂O₄)_x(P₂O₅)_1–x]_2/3

Behrends

Eckert

2014

J. Phys. Chem. C

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“…2 can be discussed assuming that germanate and phosphate components of the studied glasses may act partially independent in the glass network, analogously as in the studied binary alkali phosphate and germanate glasses [6]. The broad band centered at ∼350 cm −1 is assigned to both symmetric stretching of Ge-O-Ge bonds associated with four-and three-membered GeO 4 rings [23,24] and also to pendent PO 2 bending and in chain O-P-O bending motion [8].…”

Section: Resultsmentioning

confidence: 92%

“…Beside their applicability in optical data transmission, solid state batteries, and laser technologies, owing to their high thermal expansion coefficient, low transition temperature and high electric conductivity [1][2][3][4][5][6], phosphate-based glasses are nowadays also studied because they have great prospective for use as biomaterials [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

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Homogeneous Ag2O–2P2O5–CaO–GeO2 glass formation, structural and in vitro studies

Lucacel

Hulpus

Simon

et al. 2010

Journal of Alloys and Compounds

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“…Numerous investigators [22][23][24] have undertaken experimental and theoretical research on phosphate glasses. It was established that the network of the vitreous P 2 O 5 is formed from PO 4 tetrahedral, which are connected through P-O-P linkages forming a polymeric structure.…”

Section: Ft-ir Spectroscopymentioning

confidence: 99%

Electrical and physicochemical properties of some Ag2O-containing lithia iron silica phosphate glasses

Ibrahim

Darwish

Gomaa

2011

J Mater Sci: Mater Electron

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The present paper reports the influence of Ag 2 O addition at the expense of Li 2 O on the local structure of xAg 2 OÁ(30 -x)Li 2 OÁ10Fe 2 O 3 Á10SiO 2 Á50P 2 O 5 glass matrix (with x = 0, 0.5, 1, 1.5 and 2 mol %). The phosphate structural units of the network former are assessed from Fourier transform infrared (FT-IR) spectroscopy. The addition of Ag 2 O to the glass network matrix B1 mol % leads to the occurrence of a depolymerization process of the phosphate structure and consequently, to the appearance of a distortion of the PO 4 tetrahedra. When the content of Ag 2 O is increased from 1.5 up to 2 mol %, a remarkable polymerization process has been observed. The density, molar volume, microhardness and chemical durability have been investigated in order to study the effect of Ag 2 O/Li 2 O replacements on the physicochemical properties the studied glasses. The AC electrical properties are affected to a great extent with composition. These results are related to the internal structure of the glass samples. The conductivity, dielectric constant and dielectric loss of the studied glasses were studied using the frequency response in the interval 100 Hz-100 kHz and the effect of compositional changes on the measured properties was investigated. Measurements showed that the electrical responses of glass samples were different and complex for interpretation. The increase of Ag 2 O addition at the expense of Li 2 O contents (from 0 to 1 mol %) led to increase the conductivity, dielectric constant and dielectric losses of samples. The addition of more Ag 2 O at the expense of Li 2 O (from 1.5 to 2 mol %), resulting into decreasing the conductivity, the dielectric constant and dielectric losses of the studied glasses. The experimental data of the glass samples were argued to the internal structure of the glasses and the nature and role-played by weakening or increasing the rigidity of the structure of the sample. It could be concluded, therefore, that the AC electrical properties of the samples were influenced by the distribution of its constituents, connectivity, and number of free charges.

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The structure of alkali germanophosphate glasses by Raman spectroscopy

Cited by 96 publications

References 28 publications

Mixed Network Former Effects in Oxide Glasses: Spectroscopic Studies in the System (M₂O)_1/3[(Ge₂O₄)_x(P₂O₅)_1–x]_2/3

Mixed Network Former Effects in Oxide Glasses: Spectroscopic Studies in the System (M₂O)_1/3[(Ge₂O₄)_x(P₂O₅)_1–x]_2/3

Homogeneous Ag2O–2P2O5–CaO–GeO2 glass formation, structural and in vitro studies

Electrical and physicochemical properties of some Ag2O-containing lithia iron silica phosphate glasses

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The structure of alkali germanophosphate glasses by Raman spectroscopy

Cited by 96 publications

References 28 publications

Mixed Network Former Effects in Oxide Glasses: Spectroscopic Studies in the System (M2O)1/3[(Ge2O4)x(P2O5)1–x]2/3

Mixed Network Former Effects in Oxide Glasses: Spectroscopic Studies in the System (M2O)1/3[(Ge2O4)x(P2O5)1–x]2/3

Homogeneous Ag2O–2P2O5–CaO–GeO2 glass formation, structural and in vitro studies

Electrical and physicochemical properties of some Ag2O-containing lithia iron silica phosphate glasses

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Mixed Network Former Effects in Oxide Glasses: Spectroscopic Studies in the System (M₂O)_1/3[(Ge₂O₄)_x(P₂O₅)_1–x]_2/3

Mixed Network Former Effects in Oxide Glasses: Spectroscopic Studies in the System (M₂O)_1/3[(Ge₂O₄)_x(P₂O₅)_1–x]_2/3