Modifier Ions Research Articles

Fabrication of GdBa2Cu3O7−ẟ fine patterns by “chemically modified self-photosensitive” photolithography

In this study, GdBa2Cu3O7−ẟ (GdBCO) sol with ultraviolet (UV) sensitivity was prepared using Gd(OAC)3, Ba(OAC)2, and Cu(OAC)2 as the starting materials, methanol as the solvent, and 2,2′-bipyridine as the chemical modifier. Furthermore, chelation mechanism of the chemical modifier and metal ions in the sol was analyzed by infrared and UV absorption spectroscopy. Cu2+ in the sol was found to chelate with the chemical modifier to form a photosensitive chelate, rendering UV sensitivity to the sol. Next, the photosensitive chelate was decomposed by exposing it to UV light, and the decomposition product was barely soluble in organic solvents. By exploiting the self-sensitivity of GdBCO, fine patterns of its films were obtained (without photoresist throughout) with micron scale resolution. XRD and superconductivity performance tests revealed that compared to the GdBCO film without fine patterns, fine-patterned GdBCO fabricated herein does not exhibit significant degradation in terms of its crystal structure and superconductivity. This result indicates that fine-pattern technology developed for chemical film formation is simple in terms of process and equipment, and it does not affect the performance of the GdBCO film. Therefore, “chemically modified self-photosensitive” photolithography can be applied for the preparation of the GdBCO-based inorganic microstructure, which exhibits specific significance for the research and application of high-temperature superconductor electronic devices. In addition, during heat treatment, the technology of first introducing carbon dioxide and then water vapor also was adopted in this paper, which reduced the surface roughness of the GdBCO film.

The Structure of Gd3+-Doped Li2O and K2O Containing Aluminosilicate Glasses from Molecular Dynamics Simulations

Understanding the atomic structure of glasses is critical for developing new generations of materials with important technical applications. In particular, the local environment of rare-earth ions and their distribution and clustering is of great relevance for applications of rare earth-containing glasses in photonic devices. In this work, the structure of Gd2O3 doped lithium and potassium aluminosilicate glasses is investigated as a function of their network modifier oxide (NMO–Li2O, K2O) to aluminum oxide ratio using molecular dynamics simulations. The applied simulation procedure yields a set of configurations, the so-called inherent structures, of the liquid state slightly above the glass transition temperature. The generation of a large set of inherent structures allows a statistical sampling of the medium-range order of the Gd3+ ions with less computational effort compared to other simulation methods. The resulting medium-range atomic structures of network former and modifier ions are in good agreement with experimental results and simulations of similar glasses. It was found that increasing NMO/Al ratio increases the network modifier coordination number with non-bridging oxygen sites and reduces the overall stability of the network structure. The fraction of non-bridging oxygen sites in the vicinity of Gd3+ ions increases considerably with decreasing field strength and increasing concentration of the network modifier ions. These correlations could be confirmed even if the simulation results of alkaline earth aluminosilicate glasses are added to the analysis. In addition, the structure predictions generally indicate a low driving force for the clustering of Gd3+. Here, network modifier ions of large ionic radii reduce the probability of Gd–O–Gd contacts.

Chemical durability of borosilicate pharmaceutical glasses: Mixed alkaline earth effect with varying [MgO]/[CaO] ratio

AbstractGlass for pharmaceutical packaging requires high chemical durability for the safe storage and distribution of newly developed medicines. In borosilicate pharmaceutical glasses which typically contain a mixture of different modifier ions (alkali or alkaline earth), the dependence of the chemical durability on alkaline earth oxide concentrations is not well understood. Here, we have designed a series of borosilicate glasses with systematic substitutions of CaO with MgO while keeping their total concentrations at 13 mol% and a fixed Na2O concentration of 12.7 mol%. We used these glasses to investigate the influence of R = [MgO]/([MgO] + [CaO]) on the resistance to aqueous corrosion at 80°C for 40 days. It was found that this type of borosilicate glass undergoes both leaching of modifier ions through an ion exchange process and etching of the glass network, leading to dissolution of the glass surface. Based on the concentration analysis of the Si and B species dissolved into the solution phase, the dissolved layer thickness was found to increase from ~100 to ~170 nm as R increases from 0 to 1. The depth profiling analysis of the glasses retrieved from the solution showed that the concentration of modifier ions (Na+, Ca2+, and Mg2+) at the interface between the solution and the corroded glass surface decreased to around 40%–60% of the corresponding bulk concentrations, regardless of R and the leaching of modifier cations resulted in a silica‐rich layer in the surface. The leaching of Ca2+ and Mg2+ ions occurred within ~50 and <25 nm, respectively, from the glass surface and this thickness was not a strong function of R. The leaching of Na+ ions varied monotonically; the thickness of the Na+ depletion layer increased from ~100 nm at R = 0 to ~200 nm at R = 1. Vibrational spectroscopy analysis suggested that the partial depletion of the ions may have caused some degree of the network re‐arrangement or re‐polymerization in the corroded layer. Overall, these results suggested that for the borosilicate glass, replacing [CaO] with [MgO] deteriorates the chemical durability in aqueous solution.

ВЛИЯНИЕ СОСТАВА КРИСТАЛЛОХИМИЧЕСКОЙ СТРУКТУРЫ КАЛЬЦИЙ-ФОСФАТНОГО НАНОКОМПОЗИТА НА ФОРМИРОВАНИЕ ЭЛЕКТРОПОВЕРХНОСТНЫХ И КИСЛОТНО-ОСНОВНЫХ СВОЙСТВ

The single-phase modified nanostructured hydroxyapatites and biomimetic calcium-phosphate nanocomposite (BMHAP) doped by silicate and carbonate anions are synthesized by chemical precipitation in aqueous solutions. The chemical composition of the obtained samples is studied by energy dispersive X-ray spectroscopy using a scanning electron microscope. It is shown that the obtained molar ratios are close to the design values in all samples. The influence of different modifying ions in the crystal-chemical structure of hydroxyapatite (HAp) on the electrosurface properties of the synthesized products has been studied. Unmodified hydroxyapatite, silicate-substituted hydroxyapatite, and BMHAP particles are found to carry a negative charge in an aqueous suspension at pH = 7, while carbonate-substituted HAp particles had a positive charge. It is revealed that the introduction of silicate and carbonate anions into the HAp structure is accompanied by an increase in negative values of the zeta-potential from -1.05 to -4.29 mV. The change in the distribution of active centers on the surface of modified nanostructured hydroxyapatites is studied by the adsorption of acid-base indicators method with pKax in the range from -0.3 to +12.8. In contrast to stoichiometric hydroxyapatite, in BMHAP the neutral Bronsted centers prevails, and their concentration is 48.38 mmol-eq/g

Waveguides fabrication by femtosecond laser in Tb3+/Yb3+ doped CaLiBO glasses

Borate glasses present the ability to host various modifier ions and, therefore, are adaptable for a wide range of applications. Specifically, calcium-lithium tetraborate (CaLiBO) glasses doped with rare earths have been investigated for applications involving energy transfer processes. In this work, waveguides were inscribed by femtosecond laser microfabrication in CaLiBO glasses containing Tb3+ and Yb3+ ions, displaying emission in the green region. Single-mode guiding at 632.8 nm, with propagation losses of approximately 2.0 dB/cm, was obtained in 7.0-mm long waveguides with a diameter on the order of 2 μm, produced in the glass bulk, at approximately 100 μm below the sample surface. By coupling 488 nm light, the fabricated waveguide showed the capability of guiding the typical emission of Tb3+ ions. Such glasses containing rare earths could be suitable for the development of green light-emitting microdevices.

Role of TeO2 coordination with the BaF2 and Bi2O3 on structural and emission properties in Nd3+ doped fluoro phosphate glasses for NIR 1.058 μm laser emission

Fluoro phosphate glasses with different contents of barium and bismuth (8, 11, 14, 17 and 20 mol %) doped with Nd 3+ were prepared by melt quenching technique. Importance of these modifier ions on structural transformation were carried out using XRD, FTIR, FT-Raman and 31 P MAS NMR characterizations. 31 P MAS NMR spectra revealed that structural modifications due to Bi 2 O 3 are more when compared with BaF 2 in this fluoro phosphate glass matrix. Three phenomenological Judd-Ofelt (J-O) parameters Ω λ (λ = 2, 4, 6) have been derived from the absorption spectra of Nd 3+ doped barium and bismuth fluoro phosphate glasses. From the Judd-Ofelt parameters, transition probabilities (A), branching ratios (β) of certain transitions and radiative lifetimes of certain excited states of Nd 3+ are extracted and reported. From the emission spectra, emission cross sections (σ e ), band gains (σ e xΔλ eff ) and optical gain parameters (σ e xτ R ) were reckoned for the observed emission bands in these phosphate glasses. It is observed that barium glass resulted higher laser spectroscopic parameters (σ e , σ e xΔλ eff , σ e xτ R ) which are crucial characteristics for exploring promising laser applications. Impact of Ba 2+ and Bi 3+ on luminescent properties of Nd 3+ doped fluoro phosphate glasses has been examined in search of solid sate gain medium for laser emitting NIR light around 1.058 μm for photonic applications. •Nd 3+ doped barium and bismuth flouro phosphate glasses are prepared by melt quenching technique. •Structural analysis for present fabricated vitreous material with the help of FT-Raman, FTIR and 31 P NMR spectra. •Addition of Alkaline earth fluoride BaF 2 enhance the spectroscopic properties. •The Nd 3+ doped Barium flouro phosphate glasses could be promising host in the NIR region around 1.058 μm.

Preparation, characterization and in vitro biological response of simultaneous co-substitution of Zr+4/Sr+2 58S bioactive glass powder

In the present study, structure of zirconium-containing bioactive glass (58S-BG (Zr-BG)) with optimal fixed Zr content (5 mol.%) was modified by incorporation of strontium (Sr). These Zr and Sr-containing BGs (ZS-BGs) were synthesized by sol-gel method and substitution of Ca with modifier ions (Sr content = 0, 3, 6, 9, and 12 mol.%). The results obtained from characterization by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR), and energy-dispersive X-ray spectroscopy (EDS) techniques from surface of all the ZS-BGs revealed formation of hydroxyapatite (HA) after 7 days of immersion in the simulated body fluid (SBF) solution. Evaluation of changes in the SBF solution, by monitoring pH variations and ions҆ concentration, was in agreement with the results of morphological and structural investigations. The in-vitro biological function of synthesized BGs was studied through (MTT) assay and alkaline phosphatase (ALP) activity analysis. The results showed that all the specimens significantly stimulated proliferation and viability of MC3T3 osteoblast-like cells. Furthermore, antibacterial studies confirmed less resistance of methicillin-resistant Staphylococcus aureus (MRSA) bacteria against ZS-BGs. Eventually, the results of in-vitro bio-analysis were clarified and confirmed by two cell staining techniques of Live/Dead and Dapi/Actin. This confirmation was achieved by observing the increased quantity of live cells and their nuclei as well as the decreased number of dead cells after co-culturing with all ZS-BGs.

Analysis on the Tc Values of MPB Pb (Zr1-xTix)O3 Ferroelectric Ceramics

In this communication an attempt has been made to review, in brief, on Curie temperatures (Tc) of lead zirconatetitanate near morphotropical phase boundary. This review also includes 52/48 PZT modified by cadmium (Cd+2) in various amounts such as 5%, 10%, and 15%. We are proposing an easy method of selecting a substitution element for synthesizing modified lead zirconatetitanate (PZT) ceramics. Our investigation revealed that substitution of +3 valence elements will enhance Tc values whereas the substitution of +2 valence elements will decrease Tc. The change in Tc values is also attributed to ionic radii of modifier ions.

Crack growth in borate and silicate glasses: Stress-corrosion susceptibility and hydrolytic resistance

A double cantilever beam technique in air equipped with ultrasound modulation was used to measure the crack velocity v in borate and silicate glasses. In all glasses v and the stress intensity KI followed the empirical correlation v ~ KIn. Indicated by its smallest KI at v = 1 µm s − 1, KI* = 0.27 MPa m0.5, the silicoborate glass containing 70 mol% B2O3 was found most susceptible to stress-corrosion enhanced crack growth. Contrarily, the sodium calcium magnesium silicate glass appeared least susceptible with KI* = 0.57 MPa m0.5. No clear correlation is evident between KI*, reflecting the stress-corrosion susceptibility, and the hydrolytic resistance for all glasses under study, but values of n obtained from the present study and taken from previous literature for 35 glasses tend to decrease with increasing network modifier ion fraction. Energy dissipation during stress-corrosion enhanced crack propagation is assumed to cause this trend.

Leaching pattern of phosphate glass fertilizers with different compositions under Soxhlet distillation conditions

Abstract Glass fertilizers in the phosphate systems were melted at 900-950 °C with a soaking period of 1 h. Leaching study of these glasses with a maximum time period of 300 h was conducted under Soxhlet distillation condition with distilled water. Weight loss and the leach rates of the glass fertilizer samples were calculated from BET surface area measurements. They were in the range of 6.3x10-3 to 2.3x10-3 g.m-2.h-1 at 90 °C. The effect of different modifier ions like Na+, Fe3+, Mg2+, Ca2+, and K+ in the basic phosphate networks on melting and time of melting has been found to be evident. The pH determination ranging from 4.80 up to 7.50 of the leachate solution at ambient temperature under varying time intervals showed interesting and regular variations. The leaching study of such glasses under Soxhlet condition showed Ca2+, Mg2+, and K+ to be good candidates as modifier towards faster leaching. The findings have been corroborated in terms of ionic size, ionic radius, and hence the ionic potential of the modifier ions incorporated into the glass structure. The application of glass fertilizers was made on kharif paddy.

Structural modifications of soda‐lime silicate glasses using femtosecond pulse‐laser irradiation

AbstractFemtosecond pulse laser radiation (250 fs, 1030 nm) of alkali and alkaline earth modified soda‐lime silicate (SLS) glasses resulted in densification. The degree of density changes depends on pulse energy and glass‐network connectivity. Raman spectroscopy study of the high‐frequency region (800‐1200 cm−1) confirmed that surface densification was the result of interatomic changes in the distribution of silicon‐nonbridging oxygen (NBO) bond lengths and Si‐O‐Si bond angle distribution (BAD). Modifier valency contributes to structural rigidity and the degree of disorder a glass can incur during the deposition of high‐energy laser pulses. Varying soda content caused larger shift in the laser modified Q3 band position and width compared to the calcium modified system. Increasing laser fluence was found to affect the position of Q3 Si‐O stretching mode as well as the band width, indicating the increased degree of disorder laser pulses induce. These results underscore the role of modifier ions in the laser‐induced densification of the SLS glasses.

Structural, elastic, optical and γ-ray shielding behavior of Dy3+ ions doped heavy metal incorporated borate glasses

The effect of modifier ions in different basis have been analyzed through a new series of heavy metals incorporated borate based glasses 39H3BO3+30PbO+20MO+10Bi2O3 +1Dy2O3 (where M=Ca,Sr,Ba,Na and K) which are synthesized following melt quenching technique for radiation screening applications. The potentiality of glasses to withstand the penetration of fast moving neutrons is checked by various studies. Functional groups are identified through different stretching and bending modes of vibrations within the glass membrane through FTIR spectral analysis. In addition to that, other structural properties like Boron-Boron distance (dB−B), molar volume of oxygen (Vo), Oxygen Packing Density (OPD), optical basicity (Λth) and Bond density (nb) are calculated theoretically. The bonding nature (β) and nephelauxetic ratio (δ) values reveals that the glasses possess more of ionic linkages. The high density value exhibited by the Bismuth lead borate glasses indicates their capability to act as a good shielding material in reactors emitting hazardous radiation. Different moduli of elasticity (E, K, G, σ) values for the present glasses are calculated and the results reveal the enhancement in shielding performances when compared to other existing glasses and a comparative study is made on it. Optical studies are carried out and the absorption of Dy3+ions to different energy levels is observed and optical band gap (Eopt) values of the synthesized glasses are calculated along with the Urbach energy (ΔE) values. Radiation shielding properties of the produced glasses were investigated in terms of the mass attenuation coefficients (µm), transmission fraction (T), half value layer (HVL) and effective atomic number (Zeff) parameters. The results attained in the shielding study indicated that glass specimen with M = Ba exhibits enhanced shielding behavior as Ba owns high atomic number (Z) compared to other elements. Glass specimen with M = Na shows the poorest shielding characteristics due to the low Z of Na.

“Gamma Rays Interactions on Optical, FTIR and ESR Spectra of Alkaline Earth Binary Borate Glasses”

Abstract Alkaline earth binary borate glasses with the composition of (100-x) B2O3 + X (BaO, CaO, SrO) where x=22, 32 or 42 wt. % were prepared by melting annealing technique. Some of their physical and spectroscopic properties have been studied before and after gamma irradiation such as Density, oxygen packing density, molar and specific volumes, as well as optical UV-visible absorption, optical energy gap (Eopt), FTIR and ESR spectroscopy. The UV-visible spectra show a shifting of the optical edge to higher wavelengths with increasing the polarizability of the introduced modifier ion and the dose of gamma radiation. FTIR spectra show the vibrational bands of the structural borate groups; the triangular BO3 and tetrahedral BO4 units at 1200-1600 cm-1 and 800-1200 cm-1 respectively. ESR spectra show a constant behavior of the glasses at the low doses of radiation up to 60 kGy but show high effect of radiation at the higher doses due to the formation of more paramagnetic defects and free radicals.

Structure, luminescence and energy transfer of fluoroindate glasses co-doped with Er3+/Ho3+

This work reports on the analysis of structural and spectroscopic properties of the fluoroindate glasses co-doped with Er3+/Ho3+. Structural analysis showed that erbium and holmium ions were modifier ions and depolymerizedof the fluoroindate glass network. The energy transfer processes between rare - earth ions in fluoroindate glasses pumped by and 980 nm laser diode have been also examined. Due to partial Er3+ → Ho3+ energy transfer and superposition of Er3+: 4I11/2 → 4I13/2 (2.77 μm)+ Ho3+: 5I6 → 5I7 (2.85 μm) radiative transitions in fluoroindate glass co-doped with 0.8ErF3/1.6HoF3, a broadening 3 μm luminescence (Δλ= 201 nm) was obtained. The overall energy transfer efficiency ηET1 + ηET2 was calculated to be 95% indicating efficient sensitization of the holmium ions by erbium.

Role of modifier ion radius in luminescence enhancement from 5D4 level of Tb3+ ion doped alkali-alumino-telluroborate glasses

Alkali-alumino-telluroborate glasses with the different network modifier elements were prepared by melt–quenching method. Absorption, excitation, luminescence spectra as well as decay curves of 5D4 level were measured at room temperature. A phonon side band of 7F6 → 5D4 transition has been obtained from the excitation spectra of Tb3+ ion. The role of modifier ion radius in luminescence enhancement from 5D4 level of Tb3+ ion was discussed in detail. In prepared glasses, multiphonon relaxation rate from 5D3 level to 5D4 is enhanced in the host glasses containing modifier ions with large radius. This is main reason leading to the enhancement of luminescence from 5D4 level of Tb3+ ion in alkali-alumino-telluroborate glasses under excitation at 350 nm. Additionally, the Judd-Ofelt theory was used to estimate the features of ligand field and radiative properties of Tb3+ ion. The calculated results have shown that the 5D4→7F5 transition has potential applications for laser action and optical amplifier.

Study of the inhibitory ability of inorganic di- and polyphosphate compositions

The article considers the anticorrosive properties of inorganic di-and polyphosphate compositions in relation to St-3 steel, depending on the pH of the medium, the nature and concentration of phosphate, and the nature of the modifier ion. The research was conducted using GOST-based methods: gravimetry, potentiometry, photocolorimetry, infrared spectroscopy and scanning electron microscopy. On the basis of experimental data, quantitative indicators of corrosion process were determined: the rate of corrosion process, the degree of protection, the depth index, the coefficient of inhibition and the assessment of the stability of the formed film on the ball scale of corrosion resistance against steel. The analysis of experimental data allows to establish the influence of the above factors on the corrosion processes in the systems under study. The experimental data are supplemented by thermodynamic calculations of the corrosion process parameters, the results of which correlate well with the kinetic data of the process under study. In the course of the research work, the analysis of corrosion deposits was also carried out. The regularities established during the work contribute to the creation of effective di-and polyphosphate inhibitors with the highest degrees of protection.

Вязкость расплавов систем B2O3-CaO-NiO (FeO)

Structure of the B2O3 melt was analyzed as well as CaO modifier additives (25, 34, and 45 mass %) effect to it. As was proved, non-ring groups of associated rings proper to pure B2O3 are transformed into BO2O – metaborate triangles. The released oxide ions increase the coordination number of modifying ions, which occupy cationic vacancies place in the most disordered part of the melt greed. The B2O3–CaO–NiO and B2O3–CaO–FeO melts viscosity were measured by the method of vibration viscometry. Ratio of Boron to Calcium oxide mass fractions was taken as 3/1 and content of Nickel and Iron oxides in the range up to 5 and 20 % mass respectively. The experiments had been carried out using vibration viscometer operating in the mode of forced oscillations. The melt temperature was measured by Platinum –Platinum – Rhodium thermocouple. The measurements were carried out in cooling mode of the melt from 1800 K at 7-10 K/min speed. The viscosity temperature dependencies as well as its dependence on Nickel and Iron oxides were determined. Data processing was performed using the Table curve application software. Viscosity experimental data of the B2O3-CaO-NiO system melts for 1373, 1423, 1473, 1523, 1573 K temperatures have been described by the equation: η = a + b·exp(-cx), and for B2O3 – CaO – FeO melts by equation: η = a + b·x2 + c·exp (x) + d·exp(-x). Experimental data and calculations results show good convergence. The results are supposed to be used for describing the kinetics of metal reduction in bubbling processes, accompanied by the concentrations change of the oxides under reduction. The obtained information is useful for correction the slag melts properties in non-ferrous metal production.

Optical properties of peralkaline aluminosilicate glasses doped with Sm3+

Enhancing the fluorescence and thermo-mechanical properties of rare-earth doped aluminosilicate glasses (AS) by modifying the chemical composition with different alkaline earth oxides opens new opportunities for their application as optical devices. This paper provides a study on 1 × 1020 ions/cm3 Sm3+ doped aluminosilicate glasses, with the network modifier oxides BaO, SrO, CaO, MgO (35 mol%), Al2O3 (10 mol%) and SiO2 (55 mol%), denoted as BaAS, SrAS, CaAS and MgAS, prepared by the melt quench technique. Based on the measured UV–visible and NIR absorption spectra, the Judd-Ofelt parameters Ωλ, (λ = 2, 4, 6) were evaluated to predict the radiative properties of Sm3+ ions such as radiative transition probabilities (Arad), radiative lifetimes (τrad) and branching ratios (βR). By using the Füchtbauer-Ladenburg (FL) formula, the gain cross sections were calculated from the stimulated emission cross sections. The glass BaAS has the highest value of Ω2 which corresponds to a high asymmetry at the rare earth sites and the glass MgAS has the highest values of Ω4 and Ω6 which corresponds to a high rigidity and a low optical basicity of the glass. The same glass has the highest quantum efficiency and the highest gain cross section values of the investigated glasses. On the other hand, the glass BaAS has the smallest efficiency and gain cross section, however, it provides the lowest glass transition temperatures which would be beneficial for the production of high-quality glass. Raman spectra of the AS glasses show a broader variation of Qn species and an increasing depolymerization for glasses with network modifier ions of larger ionic radii.

Boron anomaly in the thermal conductivity of lithium borate glasses

Despite the importance of thermal conductivity for a range of modern glass applications, its compositional dependence and structural origins in modified oxide glasses remain poorly understood. In particular, the thermal conductivity of oxide glasses with network formers other than silica remain almost unexplored and no thorough connection with structural characteristics of glasses has been made. In this work, we study the thermal conductivity of binary lithium borate glasses using both experiments and classical molecular dynamics (MD) simulations. This glass system is chosen due to the nonmonotonic evolution in the boron coordination number as a function of composition and because glasses may be made in a wide compositional window. Specifically, we show that thermal conductivity exhibits a clear boron anomaly effect, as observed in both experiments and MD simulations. Thermal conduction is thus believed to mainly be promoted by the presence of fourfold coordinated boron. However, simulated vibrational density of states for the studied series suggests that the thermal conductivity is also influenced by the presence of the modifier ions based on an observed overlap between Li and O modes. Overall these results provide insights into the connection between thermal conductivity and structure of modified oxide glasses, which is the first step toward developing a model for predicting the composition dependence of thermal conductivity.

Hydrogen diffusivity in sodium aluminosilicate glasses

Hydrogen gas diffusivity of fourteen glasses of the Na2O-Al2O3-SiO2 system are studied along the joins quartz-albite-jadeite-nepheline (Qz-Ab-Jd-Np, fully polymerized) and albite-sodium disilicate (Ab-Ds, depolymerized). Density measurements show that ionic porosity decreases from 54.4% (Qz) to 51.5% (Np) and from 52.4% (Ab) to 50.2% (Ds). Hydrogen diffusivity D follows similar trends but at another scale. D at 523 K decreases from 4 × 10−12 to 3 × 10−14 m2 s−1 (Qz-Np) and from 4 × 10−13 to 3 × 10−15 m2 s−1 (Ab-Ds). Charge compensating Na+ acting as a filling agent in fully polymerized network structures leads to up to one order of magnitude higher diffusivities as depolymerized glass structures of the same SiO2 content where Na+ takes the role of a modifier ion. Temperature dependence of the diffusivity indicates that both the activation energy involved with the moving H2 molecule as well as the accessible volume in the structure contribute to this compositional trend.