Reactions of Glasses with Aqueous Solutions

Douglas, Roy; El-Shamy, T.M.

doi:10.1111/j.1151-2916.1967.tb14960.x

Cited by 269 publications

(104 citation statements)

References 4 publications

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“…It is well known that in the case of linear dependence on the square root of time, the elution mechanism is the preferential extraction of alkali, while in the case of linear dependence on time, elution is caused by the breaking of siloxane bonds. 36) In the present experiment, as shown in Fig. 5, the mass of the extracted Na + was linearly dependant on the square root of time, indicating that the elution of the Na + into the water was caused by ion exchange in Na 2 O3SiO 2 glass within 24 h. Therefore, the change in the spectra reflects the elutability of Na + at a specific site.…”

Section: Elution Analysissupporting

confidence: 54%

Inhomogeneous distribution of Na+ in alkali silicate glasses

Tokuda

Oka

Takahashi

et al. 2011

J. Ceram. Soc. Japan

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We investigated the Na + environment in sodium silicate glasses and mixed alkali silicate glasses using 23 Na multiple-quantum magic-angle spinning (MQMAS) NMR spectroscopy, ab initio molecular orbital (MO) calculations, and Na + elution analysis. The 23 Na MQMAS NMR spectra of Na 2 OxSiO 2 and (1 ¹ y)Na 2 OyM 2 O2SiO 2 (M = Li, K) glasses showed an inhomogeneous distribution of local structures around Na + , even though spectral deconvolution was impossible. The quantum chemical calculations indicated that the alkali silicate glasses contained both aggregated and isolated Na + sites. The elution behavior also supported the local structure distribution described above. These results indicated that a cation with a high cation field strength tends to aggregate in mixed silicate glasses.

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Section: Elution Analysissupporting

confidence: 54%

Inhomogeneous distribution of Na+ in alkali silicate glasses

Tokuda

Oka

Takahashi

et al. 2011

J. Ceram. Soc. Japan

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Section: Stages Of Corrosionmentioning

confidence: 99%

“…The front of the reaction zone represents the region where the glass surface sites interact with the ions in solution [12]. The top of the gel reaction zone represents the leached layer-glass interface where a counter-ion exchange occurs [12]. The glass dissolution rate is modified by the formation of the hydrated amorphous gel layers and/or secondary precipitates, e.g., metal hydroxo and/or metal silicate complexes that have reached saturation in the leachate and can precipitate on the surface of the gel layer [112,113,114,115,116,117].…”

Section: Stages Of Corrosionmentioning

confidence: 99%

Durable Glass for Thousands of Years

Jantzen

Brown

Pickett

2010

Int J of Appl Glass Sci

181

156

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The durability of natural glasses on geological time scales and ancient glasses for thousands of years is well documented. The necessity to predict the durability of high level nuclear waste (HLW) glasses on extended time scales has led to various thermodynamic and kinetic approaches. Advances in the measurement of medium range order (MRO) in glasses has led to the understanding that the molecular structure of a glass, and thus the glass composition, controls the glass durability by establishing the distribution of ion exchange sites, hydrolysis sites, and the access of water to those sites. During the early stages of glass dissolution, a "gel" layer resembling a membrane forms through which ions exchange between the glass and the leachant. The hydrated gel layer exhibits acid/base properties which are manifested as the pH dependence of the thickness and nature of the gel layer. The gel layer ages into clay or zeolite minerals by Ostwald ripening. Zeolite mineral assemblages (higher pH and Al 3+ rich glasses) may cause the dissolution rate to increase which is undesirable for long-term performance of glass in the environment. Thermodynamic and structural approaches to the prediction of glass durability are compared versus Ostwald ripening.

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“…Structural changes in historic glasses from organic pollutants 1279 alkali (Na, K) and low in stabilisers (Ca, Mg), such as the ones encountered in the NMS collection, are the most susceptible to this alteration. 5,8,11,15,16 The first stage of the process is an ion-exchange reaction between penetrating H C (or H 3 O C ) ions from the moisture and the alkali metal ions (primarily Na C or K C ), which are removed from the glass. With time, an alkaline film containing NaOH or KOH and H 2 O forms on the glass surface.…”

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confidence: 99%

Raman investigation of the structural changes during alteration of historic glasses by organic pollutants

Robinet

Coupry

Eremin

et al. 2006

J. Raman Spectrosc.

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The combination of an unstable glass composition, fluctuating humidity and a high concentration of organic pollutants is responsible for the widespread alteration of part of the glass collections of the National Museums of Scotland (NMS). The alteration has resulted in the formation of crystalline corrosion at the surface and strong modification of the chemical structure of the glass. The chemical structure before and after alteration of two soda-silicate glasses from the NMS collection was examined by Raman spectroscopy assisted by electron microprobe. Decomposition of the Raman spectra offered an insight into the modified glass structure and the mechanisms of the alteration. The acidic pollutants, acetic and formic acids, were identified as the main cause of alteration, as they provide a source of H + ions that enhanced the ion-exchange reaction. The ion-exchange reaction in the soda glasses causes leaching of sodium ions out of the structure and formation of silanols (Si-OH), but leaves the stabiliser ions such as calcium and lead ions undisturbed. The ion exchange is followed by a polymerisation reaction of the silanols inducing the formation of new Si-O-Si bonds including four-fold silica D 1 rings and the release of molecular water into the structure. The polymerisation reaction is likely to be responsible for the cracking and flaking of the surface through the tensile stresses generated in the glass structure. The alteration process, and in particular the polymerisation reaction, implies that the structural modification of the glass is irreversible. Copyright  2006 John Wiley & Sons, Ltd. KEYWORDS: historic glass; soda silicate; micro-Raman spectroscopy; alteration; organic pollutants INTRODUCTIONThe deterioration of ancient and historic glass within museum collections results in visual alteration and physical damage to the object, including development of surface iridescence, formation of crystalline corrosion products or liquid droplets depending on humidity, crizzling, cracking and flaking. In extreme cases, the entire object may disintegrate. For this reason, many museums are concerned with the stability of their glass collections and require detailed knowledge of the alteration processes to improve preservation and conservation.A survey of the glass collection of the National Museums of Scotland (NMS) showed higher-than-expected deterioration for the 19th to 20th century British, Islamic and Asian glass collections which had been kept in wooden display and/or storage cabinets under fluctuating relative Ł Correspondence to: Laurianne Robinet, The University of Edinburgh, Centre for Materials Science and Engineering, Edinburgh, EH9 3JL, UK. E-mail: l.robinet@ed.ac.uk humidity.1 The altered (unstable) glass showed significant compositional variety, and in all cases was distinguished from the unaltered (stable) glass by high alkali and low calcium and/or magnesium levels. Scientific studies of the glass collection revealed that the alteration was enhanced by high concentrations of organic pollutants (ac...

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Reactions of Glasses with Aqueous Solutions

Cited by 269 publications

References 4 publications

Inhomogeneous distribution of Na+ in alkali silicate glasses

Inhomogeneous distribution of Na+ in alkali silicate glasses

Durable Glass for Thousands of Years

Raman investigation of the structural changes during alteration of historic glasses by organic pollutants

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