Increasing Li2O Content Research Articles

Effect of Li2O on dielectric, structural and optical properties of yttrium borosilicate glasses

Composition 55SiO2-30B2O3-(x)Li2O-(15-x)Y2O3 (x = 00, 05, 10, 15) are synthesized using melt-quench technique at higher temperature (1550 °C). As-synthesized samples are sintered to form the crystalline phases at different temperature range, i.e., 800 °C and 850 °C. The density (2.40–1.57 g/cc) and molecular weight (87.79–58.40 g/mol) of samples are decreased with increasing Li2O content. The crystallinity of heat-treated glasses was confirmed by using XRD technique. As the concentration of Y2O3 is replaced by Li2O, the optical bandgap (3.79–3.41 eV) and urbach tail (0.31–0.28 eV) are decreased, while, refractive index (n) is showing increasing trend (2.33–2.42). The dielectric constant of YL- samples lies from (22–55) with losses (2–18) at room temperature. The activation energy is decreased due to conduction phenomena occurred in glass-matrix. In this research, results claimed that the prepared glass-ceramics can be applied in optoelectronics application.

Study of Conduction Mechanisms in Alkali and Transition Metal Oxides Doped Borosilicate Glasses

Objectives: To synthesise a unique set of borosilicate glasses of composition, xLi2O + 0.15SiO2 + 0.45B2O3 + 0.05ZnO + (0.35 – x) WO3; (0.25 ≤ x ≤ 0.34) and to investigate conduction mechanisms. Methods: Glasses were synthesized by melt quenching technique. From the XRD spectra samples were conformed to be non-crystalline in nature. Density has been measured by following Archimedes principle and is found to decrease with Li2O mole fractions in the range 2.900 gm/cm3 – 2.495 gm/cm3. DC-conductivity was measured for the temperature range 303K – 525 K using two probe technique. Findings: It was found that these glasses behave like semiconductors in terms conductivity variation with temperature. Conductivity decreased with Li2O content up to 0.33 mole fractions and increases for higher mole fractions. High temperature conductivity variation i.e., above ϴD/2 (ϴD = Debye’s temperature) is found to follow the Mott’s small polaron hopping (SPH) model. Activation energy for conduction above ϴD/2 is found to be in the range 0.282 eV-0.702 eV. Decrease of conductivity and activation energy with increase of Li2O content has been explained in terms of dynamic nature of network and formation of cation-polaron neutral entities. The conductivity below ϴD/2 has been found to follow Mott’s variable range hopping (VRH) models. The density of states at Fermi level derived from Mott’s VRH are found to be of the order of 1023 eV-1cm-3 which are in close agreement with reported ranges for transition metal oxides doped glasses. Novelty: A unique set of mixed conducting borosilicate glasses have been prepared and investigated thoroughly for conduction mechanisms. Keywords: Borosilicate glasses, Density, Conductivity, Activation energy, Density of states

Structural investigation of lithium borate glasses by Raman spectroscopy: Quantitative evaluation of structural units and its correlation with density

Lithium borate glass is a widely studied system, mainly due to its good ionic conductivity, thermal conductivity and thermoluminescence properties. The properties of lithium borate glass are determined by its structure, and the change of microstructure unit has great influence on its properties. In this work, the xLi2O⋅(1-x) B2O3 (0.1 ≤ x ≤ 0.48) glass was studied by Raman spectroscopy combined with peaks fitting and density analysis. Through quantitative analysis of Raman spectrum, the change in trend of each structural unit as well as the change of the tetracoordinated boron content (N4) were obtained with the increase of Li2O content. Especially, a more detailed assignment and general transformation mechanism of structural units were presented, and the common inflection points of properties (mass density, molar volume, etc.) and structural units content changes were found. The correlation between the properties (mass density, atomic density and molar volume) and the basic structural units (BØ3, BØ2O− and BØ4−) of the lithium borate glass was established by the genetic function approximation algorithm (GFA). The study on the structural units in xLi2O⋅(1-x) B2O3 (0 ≤ x ≤ 0.48) glass network and the mutual transformation mechanism between each structural unit is helpful to explore the effects on macroscopic properties as the structural units change.

Effect of Li2O addition on the phase formation, microstructure and electrical properties of 0.79Bi0.5Na0.5TiO3-0.18Bi0.5K0.5TiO3-0.03BiFeO3 ceramics

Lead-free 0.79(Bi0.5Na0.5TiO3)-0.18(Bi0.5K0.5TiO3)-0.03(BiFeO3)-x(Li2O) (BNT-BKT-BF-xLi) piezoelectric ceramics, with x between 0 and 0.4 wt.%, were prepared by the conventional solid-state reaction method. In all compositions, the samples were calcined at 800 °C for 2 h and sintered at 1100 °C for 2 h. The added Li2O affected the phase formation, microstructure, dielectric and ferroelectric properties of the BNT-BKT-BF-Li ceramics were investigated. All ceramics exhibited coexisting rhombohedral and tetragonal phases. The rhombohedral phase and the average grain size increased with increase in x. All ceramics presented polygon grain shapes with anisotropic grain growth. The depolarization temperature and the maximum temperature (T d and T m) continuously increased with increase in Li2O content. The maximum dielectric constant (ε m) decreased from 6250 to 4868 when x increased from 0 to 0.4 wt.%. The P-E hysteresis loops had their squareness factor increase with rising x, indicating a harder ferroelectric was obtained with higher Li2O doping.

Effect of Li2O on rheological properties, structure, and crystallization of mould flux for high-speed thin-slab continuous casting

ABSTRACT The effects of Li2O content on the rheological properties, melt structure, and crystallization behaviour of mould flux for high-speed thin slabs are systematically studied. The results show that when the Li2O content increases from 0.86% to 5.81%, the viscosity of the mould flux decreases, the melting range increases, and the break temperature initially decreases followed by an increase. Further study shows that Li2O can release O2− and depolymerize complex Si–O–Si and Al–O–Al structural units into Si–O and Al–O structures. Simultaneously, Li2O can compensate for the charge between Si4+ and Al3+ by providing Li+ in combination with the mould-flux network structure, making the Si–O–Al structure unit more stable. With the increase in Li2O content in the slag, the crystallization of the mould flux is inhibited at first, and subsequently, it is enhanced. When the Li2O content is 4.33%, the precipitation of Lithium metaaluminate enhances the crystallization behaviour of the mould flux.

Vibrational, thermal and optical studies of 30TeO2-39.5B2O3-(30-x)ZnO-xLi2O-0.5 V2O5 (0 ≤ x ≤ 30 mol%) glass system

A series of glasses with novel composition 30TeO2-39.5B2O3-(30-x)ZnO-xLi2O-0.5V2O5 (0 ≤ x ≤ 30 mol%) were prepared using melt quenching technique. All glasses were characterized using XRD, Fourier transform infrared (FTIR) and Raman spectroscopies, Differential Scanning Calorimetry, Optical absorption and Electron Paramagnetic Resonance. The physical properties such as density, molar volume and oxygen packing density were calculated and discussed. FTIR and Raman spectral studies were performed to study the vibrational groups present in all the glasses. DSC analysis showed that the glass transition temperature (Tg) decreases with increase in Li2O content and the high thermal stability > 150 °C was observed for all glasses. Various optical parameters were calculated and variations in these values were correlated with structural changes in the glass network as revealed by FTIR and Raman studies. The estimated spin-Hamiltonian parameters of VO2+ from EPR spectra of glasses suggest that VO2+ is in octahedral site with tetragonal distortion.

Mechanical properties and electrochemical behavior of borosilicate glass system

New synthesized borosilicate glass system within the molar percentages 50 B2O3 – (14–X) SiO2 – (20+X) Li2O –15 Na2O –1Al2O3 with X=0, 1, 2, 3, 4, 5 mol % was investigated. The amorphous identity of the samples has been checked by X-ray diffraction (XRD). The decrease of the molar volume (Vm) with increasing Li2O amount led to an increase in the calculated oxygen packing density (O.P.D). The packing density of the specimens increased also with the inclusion of Li2O. The Fourier transform infrared (FTIR) showed the transformation of BO3 to BO4 units that increased the rigidity of the prepared glass series. The ultrasound wave velocities (longitudinal (𝑣𝑙 ) and shear (𝑣𝑠 )) were assigned by the pulse-echo technique. Both (𝑣𝑙 ) and (𝑣𝑠 ) increased with increasing Li2O content because of increasing the rigidity of the glass host. The elastic Longitudinal (L), Young's (E), Bulk (B) and Shear (S) moduli besides the Micro-hardness (H) were calculated and all increased with increasing Li2O content. Ultrasonic mean velocity (𝑣𝑚𝑒𝑎𝑛) and softening temperature (Tsm) increased while Poisson’s ratio (σm) decreased with the same gradient of X. The theoretical model proposed by (Makishima-Mackenzie) and bond compression model were employed for the prepared glasses. The results from both models showed correspondence with the experimentally obtained values. The impedance spectroscopy was applied to investigate the electrochemical mode of the present glass system and to measure the conductance for all the system samples.

Effect of bismuth and lithium substitution on radiation shielding properties of zinc borate glass system using Phy-X/PSD simulation

The radiation shielding properties of zinc borate glasses with lithium oxide replacing bismuth oxide were investigated using Phy-X/PSD. The glasses have a composition of (25-x)Bi2O3-60B2O3-15ZnO-xLi2O, where x = 5, 10, 15, 20 and 25 mol%, and are coded as S1, S2, S3, S4, and S5 in increasing Li2O content. Phy-X/PSD was used to determine the mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), half value layer (HVL), effective atomic number (Zeff), tenth value layer (TVL), and mean free path (MFP) of the investigated glasses. S1 was found to have the greatest MAC and LAC values, 0.415 cm2/g and 1.868 cm−1 at 0.2447 MeV respectively, while S5 had the least, 0.115 cm2/g and 0.301 cm−1 respectively at the same energy. The maximum HVL values was found at 1.46 MeV and are equal to 2.926 cm, 3.427 cm, 3.766 cm, 4.159 cm, and 5.222 cm for S1, S2, S3, S4, and S5 glasses, respectively. The minimum HVL values occurred at the lowest tested energy, 0.2447 MeV, and increased with increasing energy, meaning that the glasses are more effective at lower energies. The Zeff values inversely correlated with the Li2O content in the glasses, following the order of S1 > S2 > S3 > S4 > S5 at all energies. At 0.41 MeV, the Zeff values are equal to 25.15, 21.52, 17.42, 12.75, and 7.35 for S1, S2, S3, S4, and S5 respectively. At all energies, TVL decreased with increasing density; for instance, decreasing from 17.347 cm to 9.718 cm when density increased from 2.613 g/cm3 to 4.503 g/cm3 at 1.458 MeV. The MFP of the zinc borate glasses were compared against other shielding glasses and it was found that the S1 glass outperformed five of the other glasses at 0.2447 MeV and six of the others at 1.458 MeV. The results proved that the S1 glass, the glass with the greatest Bi2O3 content and density, has the greatest potential for radiation shielding applications.

The effect of Li2O on the evaporation and structure of low-fluoride slag for vacuum electroslag remelting

Fluoride evaporation of CaF2–CaO–Al2O3–MgO–TiO2-(Li2O) slag with different Li2O contents for vacuum electroslag remelting was investigated by thermogravimetry (TG), differential scanning calorimetry (DSC), and mass spectrometer (MS) measurements in conjunction with thermodynamic analysis, and the effects of Li2O on the melting temperature and viscosity of slag were studied. Furthermore, the variation of slag structure was analyzed by Fourier transformation infrared (FTIR) spectroscopy. The results show that, with the increase in Li2O content from 0 to 5.15 wt%, the evaporation of fluoride from the molten slag increased significantly, melting temperature and viscosity of slag decreased. Moreover, the evaporating species from Li2O-bearing slag were mainly LiF and CaF2 under a vacuum of 10 Pa. LiF evaporation was generated rapidly from molten slag due to the high vapor pressure of LiF when the temperature exceeded 800 °C, and the evaporation of CaF2 occurred above 1000 °C. Higher vacuum could increase the evaporation of fluoride. The vapor pressures were in the following sequence: LiF > CaF2 > MgF2 >AlF3 > AlOF. Additionally, FTIR analyses revealed that the O2− provided by Li2O would depolymerize [AlO4]-tetrahedral structures from Q4 units to Q3 and Q2 units, leading to decreasing the viscosity consequently.

Effect of Li2O content on structural and optical properties of Li2O-TeO2-As2O3-B2O3 glasses

Arsenate-based alkali borotellurite glasses with the general formula xLi2O-(30−x)TeO2-10A2O3-60B2O3, where 5 ≤ x ≤ 25, were formulated by the conventional melt quenching technique. The glassy nature of the samples was confirming by X-ray diffraction measurements. The influence of Li2O content on the Fourier transform IR, optical, and thermal properties, density, and other related properties of the prepared glasses was studied. The results reveal that the density and molar volume decrease and the glass transition temperature increases with increasing Li2O content This can be attributed to the difference in the ionic radii of lithium and tellurium oxides. The variation in the indirect optical bandgap and band tail with Li2O content is discussed in relation to the glass structure. On the basis of the values obtained for αO2−, the optical basicity, and the interaction parameter, the present glasses were termed normal ionic (basic) glasses. Fourier transform IR spectroscopy of the present glasses revealed that the borate network is affected by the replacement of TeO2 by Li2O. It was found that the fraction of four-coordinate boron atoms decreases and the fraction of three-coordinate boron atoms increases with increasing Li2O content.

Investigation of fluoride evaporation from CaF2\u2013CaO\u2013Al2O3\u2013MgO\u2013TiO2\u2013(Li2O) slag for electroslag remelting

The isothermal kinetics of fluoride evaporation from CaF2–CaO–Al2O3–MgO–TiO2–(Li2O) slag with varying Li2O content were investigated in the temperature range 1743–1803 K by thermogravimetric analysis. Thermodynamic calculations and viscosity measurements were applied for studying the evaporation mechanism of fluoride. The results showed that the evaporation ratio increases with increasing Li2O content and temperature. The volatile constituents from the molten slags, mainly LiF and CaF2, were detected and their concentrations calculated. The fluoride evaporation is primarily affected by the vapour pressure of LiF and CaF2, viscosity of the slags, and melt-component activities under given experimental conditions. On the other hand, mass transfer of the gas is not the rate-controlling step that affects fluoride evaporation from the slags. The activation energy for fluoride evaporation gradually decreased from 193 ± 11 to 113 ± 3 kJ mol−1 as the Li2O content in the slags increases from 0 to 5.48 wt%. These results hold great theoretical significance for developing low-fluoride slags for electroslag remelting.

Raman Spectroscopic and Theoretical Study of Scandium Fluoride and Oxyfluoride Anions in Molten FLiNaK.

The speciation in the FLiNaK-ScF3 and FLiNaK-ScF3-Li2O melts above 873 K was investigated by Raman spectroscopy and density functional theory (DFT) calculations. Binary scandium fluoride anions in the form of ScF52- and ScF63- were identified in molten FLiNaK containing 20 mol % ScF3, which were not affected by either temperature or alkali cations in molten fluoride. With the addition of Li2O into the FLiNaK-ScF3 (20 mol %) melt, ternary scandium oxyfluoride anion Sc2OF62- was formed and dominated the spectrum, and it was characterized to possess a linear Sc-O-Sc geometry with two ScF3 moieties bridged by a single oxygen atom. Further increase in Li2O content to 40 mol % resulted in the formation of the second oxyfluoride anion Sc2O2F64- containing a rhombic Sc2O2 ring, while the Raman bands due to Sc2OF62- disappeared. When the Li2O concentration went beyond 40 mol %, the sample was no longer homogeneous due to the appearance of insoluble scandium oxide on the surface of the melt, suggesting that scandium oxide is formed via the reactions of ScF52- and ScF63- with O2- in molten FLiNaK mediated by Sc2OF62- and Sc2O2F64-.

Effect of replacement of Bi2O3 by Li2O on structural, thermal, optical and other physical properties of zinc borate glasses

Zinc bismuth borate glasses modified by lithium oxide with composition (25-x) Bi2O3–60B2O3–15ZnO-xLi2O, where, x = 5, 10, 15, 20 and 25 mol% have been synthesized using standard melt quenching technique. Amorphous nature of the glass samples has been ascertained by appearance of broad hump in X-ray diffraction patterns. FTIR and Raman studies advocated that glass structure is mainly built of [BO4], [BO3] and [ZnO4] structural units, however, Bi2O3 exists primarily as [BiO6] octahedral units. The glass transition temperature (Tg) shows a non-linear variation with increase in Li2O content. Trend in the values of ‘Tg’ is in accordance with change in structure of glass matrix (i.e. fraction of [BO4] units (N4) on addition of Li2O). The values of density (ρ), molar volume (Vm) and crystalline volume (Vc) are found to decrease with increase in Li2O content. The percentage value of transmittance is found to increase with increase in Li2O content. Optical band gap energy ‘Eg’ values has been determined from fitting of experimental data with Tauc’s relation and Hydrogenic excitonic model (HEM) and are found in the range of 2.432–3.211 eV. The HEM model shows good agreement with experimentally observed data, indicates the exciton formation in studied glass system. The values of Urbach energy (ΔΕ) have been estimated by fitting of experimental data with a new empirical relation and its values are found in the range of 0.194 eV–0.294 eV. The values of metallization criterion (M) were found in the range of 0.349–0.401, suggesting that the prepared glasses may be considered as potential candidate for non-linear optical applications.

Effect of network structure on dynamics of lithium ions in molybdenum phosphate mixed former glasses

In this work we have studied the effect of network structure on the transport properties of Li2O-P2O5-MoO3 mixed former glasses. We have used Fourier Transform Infrared (FTIR) and Raman spectroscopy to study the network structure. We have measured ac conductivity and dielectric spectra for a wide range of temperature and frequency. We have observed that the conductivity increases and the activation energy decreases with the increase of Li2O content in the composition. The time temperature superposition has been verified using the scaling formalism of the conductivity spectra. We have calculated microscopic lengths of ion dynamics such as the characteristic mean square displacement of mobile ions and the spatial extent of localized motion within the framework of the linear response theory and correlated them with the ion transport properties. Also we have given a qualitative description for the correlation of the ionic transport with the relative strengths of structural units.

Structure investigation of CaO-SiO2-Al2O3-Li2O by molecular dynamics simulation and Raman spectroscopy

As a common flux, Li2O plays an important role in improving the physical and chemical properties of metallurgical slag. A variation of structural units and action mechanisms of Li in a CaO-SiO2-Al2O3-Li2O slag system is investigated using molecular dynamics (MD) simulation and Raman spectroscopy. We studied five glass compositions where the Li2O concentration varied from 0 to 16 mol%. Molecular dynamics simulation results show that Li2O plays the role of depolymerizing the microstructure of the melt. The Li+ takes precedence over Ca2+to compensate for the excess negative charge in the [AlO4]5− tetrahedral structure. The bond angles vary regularly with increasing Li2O content. Raman spectroscopy results show that the increase of Li2O promotes the transformation of Al-O-Si structural units to Al-O-Al structural units, which confirms that Li+ can better balance the charge of [AlO4]5− structure in slag. Therefore, Li+ also plays a role in stabilizing the [AlO4]5− tetrahedral structures.

Low Li2O content study in Li2O-Al2O3-SiO2 glass-ceramics

The price of lithium-containing minerals and other chemical materials continues to increase, resulting in an increase in the production cost of Li2O-Al2O3-SiO2 (LAS) system glass-ceramics. In the LAS glass-ceramics component, the reduction in the amount of Li2O used can reduce the cost of the product. It is worthwhile to study whether it is possible to prepare glass-ceramics with low expansion properties under low Li2O content. The effect of Li2O content on the glass-ceramics of LAS system was studied. In this paper, spodumene was used as the main raw material, and TiO2 and ZrO2 were added as crystal nucleating agents to prepare transparent glass-ceramics with low expansion coefficient. The effects of the change of Li2O content on the crystal phase and microstructure of glass-ceramics were investigated by XRD, DSC, FTIR and SEM. The results show that the main crystalline phase of the low expansion transparent glass-ceramics is β-quartz solid solution. When Li2O content is in the range of 2.99 wt% to 4.13 wt%, low expansion glass ceramics can be prepared by an appropriate method. With the increase of Li2O content, the average coefficient of thermal expansion (CTE) in the temperature range of 30 °C–300 °C shows a decreasing trend. When Li2O content is in the range of 3.51 wt% to 4.13 wt%, the thermal expansion coefficient of the glass ceramics is extremely small, and even a negative expansion coefficient occurs.

Structural and Optical properties of P2O5-ZnO-Na2O-Li2O glasses

The transparent glasses of composition 40P2O5-20ZnO-(40-x)Na2O-xLi2O have been prepared using conventional melt quenching technique (where 0 ≤ x ≤ 25 Li2O mol. %). The prepared glass samples were characterized by x-ray diffraction (XRD), differential thermal analysis (DTA), UV-VIS optical absorption and Fourier transform infrared spectroscopy (FTIR). The differential thermal analysis (DTA) studies showed that the glass transition temperature (Tg) decreases from 558K to 546.7K as the content of Li2O increases to 25 mol.% Li2O . The density and oxygen packing density measurements are found to be increase while the molar volume decreases with increasing of Li2O content. The FTIR studies revealed that these glasses consist of Q3, Q2, Q1 and Q0 structural units. Absorbance of investigated glasses was measured and used to estimate their optical absorption coefficient and optical energy gap. The optical studies revealed that the indirect optical band gap (Eg) decreases from 3.33-2.64 eV and Urbach energy increases from 0.46-2.4eV with increase of Li2O content from zero to 25 mol.% Li2O.

Study of the optical properties of Li2O modified P2O5-Na2O glasses

Optical characteristics of the prepared glasses of composition 55 P2O5 – (45-x) Na2O – x Li2O were ( 0 ≤ x ≤ 35 mol% ) have been investigated by X-Ray diffraction (XRD), differential thermal analysis (DTA), density (ρ), molar volume (Vm), optical packing density (OPD), UV spectroscopy and Fourier transform infrared (FTIR). The FTIR studies revealed the vibrational modes of prepared glass samples. Absorbance of investigated glasses was measured and used to estimate their optical absorption coefficient and optical energy gap. The optical studies revealed that the indirect optical band gap (Eopt) increases from 3.2-3.5 eV and the Urbach energy decreases from 1.133-0.838 eV with increase of Li2O content from zero up to 35 mol% Li2O.

Synthesis and characterization of Li2O modified sodium phosphate glasses

The transparent glasses 55 P2O 5 - (45-x) Na2O - xLi2O where (x=0, 3, 10, 15, 30, 35) were prepared by conventional melt quenching technique. Structural and characterization have been investigated by using X-Ray diffraction (XRD) and the results show that all samples are amorphous structure. The glass transition (Tg) and crystallization temperature (Tc) are evaluated using the differential thermal analyzer (DTA), which indicate that 15 mol% Li2O contained glasses exhibits maximum thermal stability h’ of glass samples. Density, molar volume and oxygen packing density insure that Li2O incorporated in sodium phosphate glass by increasing Li2O content. The ac and dc electrical conductivity and dielectric constants of the prepared glass samples have been investigated. The variation of dc conductivity with the concentration of Li2O mol% passes through a maximum at 15 mol% Li2O. Temperature dependence of the dc conductivity of these glasses is found to obey the Arrhenius law. It reveals that the values of activation energies ΔEdc1 and ΔEdc2 at low and high temperatures lie in the range 0.452-0.93 eV. Also it was found that the values of σdc to be the same as the values obtained from the impedance study. Conductivity mechanism for grain resistance at room temperature was discussed using Cole-Cole plot. To determine the conduction mechanism, the ac conductivity and its frequency exponent have been analyzed by correlated barrier hoping model (CBH). It was found that the exponent (s) has values between 0.62-0.9; consequently the (CBH) seems to be the most interesting model related to the obtained results. The variation of dielectric constants e’ and e’’ with the concentration of Li2O mol% pass through a maximum at 15 mol% Li2O and this result would be discussed by means of dielectric polarization mechanism of material. The maximum value of the maximum barrier height Wm obtained from Guitini equation was found to increase with increasing of Li2O mol%.

Correlation between ion transport and network structure of Li2O-P2O5 glasses

In the present work we have studied ion transport and their correlation with network structure of Li2O-P2O5 glasses. We have measured the ac conductivity of the glasses for wide ranges of temperature and frequency. The conductivity shows a crossover from dc to dispersive behavior with the increase in frequency. We have observed that the dc conductivity and the crossover frequency obey Arrhenius relation with same activation energy. We have calculated characteristic lengths of ion transport, such as the characteristic mean square displacement of mobile ions and the spatial extent of localized motion, within the framework of linear response theory. We have observed that both the length scales decrease with the increase in Li2O content in the glasses. We have also investigated FTIR and Raman spectra to study the structure of glassy network and established a simple correlation between transport properties and network structure of the glasses.