Insight into sodium silicate glass structural organization by multinuclear NMR combined with first-principles calculations

Angeli, Frédéric; Villain, Olivier; Schuller, S.; Ispas, Simona; Charpentier, Thibault

doi:10.1016/j.gca.2011.02.003

Cited by 120 publications

(143 citation statements)

References 81 publications

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“…The slight shift in the Si-O-Si bending mode from 496 cm −1 in the annealed sample to 500 cm −1 in the asreceived fibers, suggests that the average Si-O-Si angle decreases with the increase of glass fictive temperature. 45 It has been reported that Si-O-Si bond angles tend to be smaller with the increase of Na in the vicinity of the Si groups, 46 which is in agreement here with the additional Na near Si in the as-received fibers coming from charge compensation of BO 4 groups in the annealed fibers.…”

Section: Discussionsupporting

confidence: 90%

Effect of thermally induced structural disorder on the chemical durability of International Simple Glass

et al. 2018

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While the influence of silicate oxide glass composition on its chemical durability is increasingly known, the contribution of structure only is less well understood, yet is crucial for an accurate description of aqueous alteration mechanisms. The effect of structural disorder can be investigated by varying the thermal history of the glass. Furthermore, the structural changes generated by selfirradiation in nuclear glasses can be compared with those induced by fast quenching. In the context of deep geological disposal of vitreous matrices, it is then challenging to address the structural impact on glass durability. Here, a borosilicate glass, the International Simple Glass, was fiberized to obtain a rapidly quenched sample. The quenching rate and fictive temperature were evaluated from in situ Raman and Brillouin spectroscopies. Multinuclear nuclear magnetic resonance was used to obtain insight into the effect of quenching on the pristine and altered glass structure. Higher bond angle distribution and lower mixing of alkalis were observed in the fast quenched glass. Some of AlO 4 groups are then Ca-compensated, while a part of BO 4 is transformed into BO 3 units. The structural modifications increase the hydrolysis of the silicate network occurring in the forward rate regime at 90°C by a factor of 1.4-1.8 depending on the pH value. Residual rate regime is similarly affected, more significantly at the beginning of the experiments conducted in silica saturated solutions. These findings prove that the reactivity of glass remains controlled by its structure under the various alteration regimes.

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Section: Discussionsupporting

confidence: 90%

Effect of thermally induced structural disorder on the chemical durability of International Simple Glass

et al. 2018

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“…In literature, molybdenum has a compounding effect on phase separation, not only by inducing precipitation of crystalline molybdates at high concentrations, but also by increasing the immiscibility temperature per mol of MoO 3 and lowering the viscosity and glass-transition temperature (T g ) of the melt [20]. It is also found to affect the glassy matrix by increasing network polymerization through a reduction of NBOs [17,23,60].…”

Section: Phase Separationmentioning

confidence: 99%

“…Due to charge, mobility, size and sterics (BO 4 ) − prefers Na + ions as charge balancers. This preference thus enables the incorporation of Ca 2 + ions into molybdates [4,23,24]. It is observed that an increase of B 2 O 3 will reduce the tendency of Na 2 MoO 4 crystallization and increase the crystallization of CaMoO 4 in soda-lime borosilicates [10,24].…”

Section: Introductionmentioning

confidence: 99%

Impacts of composition and beta irradiation on phase separation in multiphase amorphous calcium borosilicates

Patel

Boizot

Facq

et al. 2017

Journal of Non-Crystalline Solids

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A B S T R A C TBorosilicate glasses for nuclear waste applications are limited in waste loading by the precipitation of watersoluble molybdates. In order to increase storage efficiency, new compositions are sought out that trap molybdenum in a water-durable CaMoO 4 crystalline phase. Factors affecting CaMoO 4 combination and glass-inglass phase separation in calcium borosilicate systems as a function of changing [MoO 3 ] and [B 2 O 3 ] are examined in this study in order to understand how competition for charge balancers affects phase separation. It further examines the influence of radiation damage on structural modifications using 0.77 to 1.34 GGy of 2.5 MeV electron radiation that replicates inelastic collisions predicted to occur over long-term storage. The resulting microstructure of separated phases and the defect structure were analyzed using electron microscopy, XRD, Raman and EPR spectroscopy prior to and post irradiation. Synthesized calcium borosilicates are observed to form an unusual heterogeneous microstructure composed of three embedded amorphous phases with a solubility limit~2.5 mol% MoO 3. Increasing [B 2 O 3 ] increased the areas of immiscibility and order of (MoO 4 ) 2 − anions, while increasing [MoO 3 ] increased both the phase separation and crystallization temperature resulting in phases closer to metastable equilibrium, and initiated clustered crystallization for [MoO 3 ] > 2.5 mol%. β-irradiation was found to have favorable properties in amorphous systems by creating structural disorder and defect assisted ion migration that thus prevented crystallization. It also increased reticulation in the borosilicate network through 6-membered boroxyl ring and Si ring cleavage to form smaller rings and isolated units. This occurred alongside an increased reduction of Mo 6 + with dose that can be correlated to molybdenum solubility.In compositions with existing CaMoO 4 crystallites, radiation caused a scattering effect, though the crystal content remained unchanged. Therefore β-irradiation can preferentially prevent crystallization in calcium borosilicates for [MoO 3 ] < 2.5 mol%, but has a smaller impact on systems with existing CaMoO 4 crystallites.

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“…Taking this into consideration, one can notice that N-ZK7 has more BO 4 (1B, 3Si) while N-BK7 and S-BSL7 have a predominance of BO 4 (0B, 4Si). The 29 Si signal for Borofloat and N-ZK7 corresponds to mostly Q4 contributions while for the two other materials the band which is centered around -100ppm is certainly generated by a mix of Q3 and Q4 units [18] [19] [20].…”

Section: Pristine Glassesmentioning

confidence: 99%

High thermal neutron flux effects on structural and macroscopic properties of alkali-borosilicate glasses used as neutron guide substrate

Boffy

Peuget

Schweins

et al. 2016

Nuclear Instruments and Methods in Physics Research Section B:

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The behaviour of four alkali-borosilicate glasses under homogeneous thermal neutron irradiation has been studied. These materials are used for the manufacturing of neutron guides which are installed in most facilities as devices to transport neutrons from intense sources such as nuclear reactors or spallation sources up to scientific instruments. Several experimental techniques such as Raman, NMR, SANS and STEM have been employed in order to understand the rather different macroscopic behaviour under irradiation of materials that belong to a same glass family. The results have shown that the remarkable glass shrinking observed for neutron doses below 0.5 · 10 18 n/cm 2 critically depends upon the presence of domains where silicate and borate network do not mix.

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Insight into sodium silicate glass structural organization by multinuclear NMR combined with first-principles calculations

Cited by 120 publications

References 81 publications

Effect of thermally induced structural disorder on the chemical durability of International Simple Glass

Effect of thermally induced structural disorder on the chemical durability of International Simple Glass

Impacts of composition and beta irradiation on phase separation in multiphase amorphous calcium borosilicates

High thermal neutron flux effects on structural and macroscopic properties of alkali-borosilicate glasses used as neutron guide substrate

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