Historical Glass Research Articles

Latest advancements in the application of analytical science to ancient and historical glass production

Major recent developments in the archaeometry of ancient and historical glass production are outlined, and examples of methods which are set to determine the future agenda of glass studies are presented. In the past twenty years there has been a step-change in the quantity and quality of archaeometric data for glass production, allowing researchers to address larger-scale questions. Quantitative chemical analyses, including trace element analysis, are increasingly being used to reconstruct not only provenance, but also production techniques, contamination, and recycling; isotope analysis is being used to challenge previous assumptions about provenance and develop approaches more rooted in geochemistry; and novel analytical techniques including ToF-SIMS and portable laser ablation have great future potential if applied to the correct questions. Finally, the use of handheld, portable-XRF is increasing the range of questions that can be asked in the field, from production site survey to sample selection, and the analysis of in situ glass windows.

Brass and Glass: Crystal Structure Solution and Phase Characterisation of the Corrosion Product Zn4Cu3(Zn1–xCux)6(HCOO)8(OH)18·6(H2O)

AbstractInvited for the cover of this issue is Sebastian Bette from the Max Planck Institute for Solid State Research, Stuttgart, Germany. The cover image shows a picture and structure of a corrosion phase formed at the contact between historic glass and brass.

Brass and Glass: Crystal Structure Solution and Phase Characterisation of the Corrosion Product Zn4Cu3(Zn1–xCux)6(HCOO)8(OH)18·6(H2O)

The title compound, Zn4Cu3(Zn1–xCux)6(HCOO)8(OH)18·6(H2O), also denoted as “Zinc C”, a previously unknown corrosion phase of brass in contact with glass, was found on four different historic objects stored in three different collections. Model experiments demonstrated that formaldehyde emitted e.g. from wooden cabinets undergoes a Cannizarro reaction in the alkaline surface film on the historic glass making formate available for the formation of this corrosion phase. The crystal structure of “Zinc C” was solved ab initio from X‐ray powder diffraction data. From the crystal structure and EDX analyses, a phase composition of Zn4Cu3(Zn1–xCux)6(HCOO)8(OH)18·6(H2O) was derived. Zinc C crystallizes in a trigonal unit cell in space group R3(148) with lattice parameters of a = 10.9185(1) Å, c = 27.5058(4) Å, and V = 2839.74(6) Å3. Layers of edge sharing MO6/3 octahedra with voids capped by Zn(HCOO) forming Zn(HCOO)(OH)3/3 tetrahedra are the main motif in the structure. The zinc/copper ratio of the corrosion phase “Zinc C” can vary between 10:3 and 4:9, due to a partial occupational disorder between copper and zinc in the crystal structure.

Elemental distribution of the greenish-Thai decorative glass

Glasses have been used in ornaments and decorations in Thailand for several hundred years, especially various colors of decorative glass which called Ancient Thai Glass (ATG) that made by Thais were found as architecture components of historical materials. Nowadays, the ATG has been almost broken and no products. Restoration with glass for conservation can be found with the modern imported glass (MIG) which bought from the market that brought from the foreign countries. However, it was shown that the colors of ATG were unchanged for hundreds of years, while as those of MIG were mostly changed within ten years. In this work, scanning electron microscope coupled with energy dispersive X-ray fluorescence spectrometer (SEM-EDX) was used to characterize the structure and composition of the greenish-ATG compared with those of MIG. It was found that the glass substrate of the ATG was lead-based glass, while as that of the MIG was soda-based one. It was revealed that the green coloration came from the Cu, Fe and Cr ions that doped into the glass matrix that confirmed with either the EDX or line scan. The results from this work are used as information that understanding the characteristics and how their production. X-ray fluorescence spectroscopy can be applied successfully in the historical glass study. It can be concluded that this technique can be applied successfully in the field of archaeology.

Exploring Bristol’s historic glass industry: archaeological investigation at the Soap Boilers’ and Hoopers’ glasshouses, and the Powell & Ricketts’ Bottle Works, Avon Street, Glass Wharf, Bristol

SUMMARY: In 2007, extensive archaeological excavation was undertaken on an important post-medieval glassworking site at Glass Wharf, Bristol. The excavation exposed remains relating to a series of glassworks dating between the early 18th and early 20th centuries and, significantly, uncovered a sequence of five glass-melting furnaces and covering structures, which together reflect wider changes in glassmaking technology throughout these periods. Detailed scientific analysis of glassworking debris from the excavation has also been undertaken, which provides much-needed detail on the development of recipes and raw materials used in bottle manufacture during the 18th and 19th centuries.

Characterization of the alteration processes of historical glasses on the seabed

Glass objects are common in shipwrecks since they are associated with ordinary glassware or commercial products. The alteration pathologies of historical glasses from two wrecks from the Mediterranean Sea were analyzed to characterize their alteration mechanisms. The results of this research proved that the alteration layers presented a moderate content of Na2O, similar to the average salinity of the ocean, and a high content of Al2O3 due to an extremely basic environment during the corrosion process. The biofouling layer protected the glass surfaces. Dark deposits with a high content of MnO were observed in the most instable glass.

Composition of Crystal Glass Made in the Middle of the 19th Century at the Gus-Khrustalnyi Factory

This is the first study of a crystal glass composition, as well as its thermal and spectral (Raman spectra and fluorescence) characteristics, produced at the Gus-Khrustalnyi factory in the middle of the 19th century. The sample studied is a potassium-calcium glass with a low lead content. The formula for such a composition was first developed in Central Europe in the second half of the 17th century and then improved at the beginning of the 18th century. The possibility to use a portable XRF spectrometer to analyze historical glass is demonstrated.

Microcrystals of antimony compounds in lead–potassium and lead glass and their effect on glass corrosion: a study of historical glass beads using electron microscopy

Crystalline inclusions of antimony compounds in lead glass of the nineteenth century have been investigated by means of transmission electron microscopy, scanning electron microscopy, X-ray microanalysis, electron backscatter diffraction and microcathodoluminescence. Microcrystallites of orthorhombic $$\hbox {KSbOSiO}_4$$ (KSS) with the sizes ranging from about 200 nm to several micrometers have been detected in lead–potassium glass of turquoise seed beads prone to a glass disease causing the irrecoverable deterioration of beaded articles kept in museums. The KSS crystals have high number density and tend to form large colonies. Crystallites of cubic $$\hbox {Pb}_2\hbox {Fe}_{0.5}\hbox {Sb}_{1.5}\hbox {O}_{6.5}$$ have been detected in stable yellow lead glass beads. Their number density and sizes are much less than those of the KSS particles observed in turquoise glass; they do not form large clusters. We have come to conclusion that KSS precipitates are responsible for the internal strain-induced corrosion of turquoise lead–potassium glass eventually resulting in crumbling of beads to sand particles. The following scenario explains this phenomenon: $$\hbox {K}^+$$ and $$\hbox {Sb}^{5+}$$ used for glass doping form KSS crystallites during glass melting; tensile strain arising in the glass matrix during cooling because of difference in temperature coefficients of linear expansion of glass and KSS crystals gives rise to crack formation and in course of time results in glass falling apart to heterogeneous pieces. Small crystallites of $$\hbox {Pb}_2\hbox {Fe}_{0.5}\hbox {Sb}_{1.5}\hbox {O}_{6.5}$$ cannot induce a sufficient strain to break yellow lead glass, and internal cracks do not arise in this glass during its cooling. This may explain the stability of yellow lead glass.

The role of different network modifying cations on the speciation of the Co2 + complex in silicates and implication in the investigation of historical glasses

In the last decades the speciation of the cobalt complex in a glass matrix has been extensively studied. Bivalent cobalt ions in glasses of different composition commonly adopt a tetrahedral coordination, though hexa- or penta-coordinated species are also possible. Changes in the absorbance spectrum of Co-doped glasses were attested in previous studies according to the introduction of different modifying cations. A shifting of the first sub-band characterizing the typical triplets of tetrahedral Co2+ ions in both the visible and near infrared regions was observed, but discrepancies in literature suggested a relevant role of glass composition on the definition of the optical signature of cobalt. Co-doped glasses with different composition (soda-lime, potash-lime, mixed alkali and ZnO-Na2O-CaO-SiO2) were studied via Fiber Optic Reflectance Spectroscopy (FORS). Pseudo-Voigt functions were used for the deconvolution of the absorbance spectra and the features of the bands characteristic of each cobalt complex were investigated. The structural role played by each modifying cation and the fundamental implications of glass basicity on the speciation of different Co-complexes were stressed. Changes in glass structure resulted in different equilibria between the three absorbing species whose specific optical signatures in the 480–530nm region interact to determine the resulting absorbance spectrum.

The Corning Archaeological Reference Glasses: New Values for “Old” Compositions

The Corning Archaeological Reference Glasses are widely used as standards in the chemical analysis of archaeological and historical glasses, as their compositions were designed to approximate those of major glass types in antiquity. Since their development in the 1960s, their compositions have been revisited and updated. This paper provides a brief overview of the Corning glasses, and addresses two of the last three elements to be re-evaluated: the recommended values for the concentrations of SO3 and Cl were, until now, based on theoretical values. Data for these elements were collected using electron microprobe, and used together with published data to suggest new values. Finally, a complete list with the most up-to-date compositions for the four Corning glasses is compiled for the benefit of other analysts.

The Influence of Selected Organic Compounds on the Corrosion of Historical Glass Based on Their State of Preservation

The Influence of Selected Organic Compounds on the Corrosion of Historical Glass Based on Their State of Preservation

Effect of soil pH on the degradation of silicate glasses

AbstractThis paper reports the research on the physical‐chemical response of silicate glasses subjected to the action of three natural soils types: acidic, neutral, and basic. The main goal of the study was to characterize the corrosion mechanisms acting upon glasses formulated with chemical compositions that are commonly found in historical glasses through an accelerated aging test that replicates natural burial. Resulting data showed a distinct and recognizable response of each glass type, with pH as the key variable for glass corrosion. Results can be of great significance to historical glass studies, especially in choosing suitable conservation strategies for archeological findings.

Conservation of a rare nineteenth-century iron-framed curvilinear glasshouse

ABSTRACTThe early nineteenth century saw a period of rapid advances in the science and technology of horticulture. The implementation of this development lay largely in the hands of the landed gentry with wealth and resources. They also had access to a flow of information to feed and guide their ambitions. One of the most influential contributors in the first quarter of the century was John Claudius Loudon, a Scot of prodigious energy, experimenting and sharing his ideas with anyone who could help develop and carry forward his thinking. In 1817 he published Remarks on the Construction of Hothouses, advocating the use of wrought-iron glazing bars that could be bent in any direction without loss of strength, making curvilinear roofs possible. By 1830, about the time Felton Park glasshouse was built, Loudon’s ideas had been fully absorbed by the horticultural industry and had initiated a mania for building glasshouses in iron for their light and elegant appearance.Though iron-framed structures were likely to survive longer than contemporary timber frames, very few iron glasshouses remain in the UK. Though the significance of this building has been recognised in its designation with the potting Shed as a Grade II* Listed Building, it had suffered a long period of neglect threatening irreversible decay and destruction. In 2008 English Heritage included the buildings in the North East Region Heritage at Risk Register.The recovery of the glasshouse reflects a major effort by an enthusiastic new private owner with the support of Historic England, the Heritage Lottery Fund, The Country House Foundation and Northumberland County Council. A Trial Project was set up in September 2014 to explore the scope of work necessary, to inform the technical requirements of the full contract and to arrive at an affordable conservation strategy respecting equally the integrity of the iron frame and the historic glass. The main contract was completed in October 2015 and the building has returned to horticultural use.

Fungi as deterioration agents of historic glass plate negatives of Brandys family collection

Microbiological deterioration was observed on a historic collection of retouched glass plate negatives. The collection came from a burnt manor house that belonged to the Brandys family before World War IInd. The photographs were taken at the end of 19th century. The collection consists of 35 glass plate negatives, 4 of which were examined for possible presence of microorganisms. The current state of the negatives indicated that the collection may have been flooded. Initially, the viability of the microorganisms on the plates was examined using luminescence adenosine phosphate assay. The fungi were isolated and identified with molecular biology methods as Trichoderma longibrachiatum, Hypocrea lixii, Aspergillus versicolor, Penicillium sp. As the historic negatives were covered with a protective varnish layer, the impact of the isolated fungi on test negative plates covered with dammar and sandarac varnishes, and on a gelatine image layer were examined. The most effective in degradation of gelatine emulsion was T. longibrachiatum. All of the investigated microorganisms quickly decomposed silver image in gelatine layer not covered with varnish in opposite to slower decomposition of silver image in gelatine layer covered with sandarac and dammar varnishes. UV-induced luminescence observation confirmed that the microorganisms quickly decomposed gelatin layer not covered with varnish. The cracking of varnish was the result of fungal activity within gelatin, however, some fungi also attacked the varnish itself.

Structural contribution of glass in Saint-Hubertus Galleries

Many of the glass-covered iron and steel frames from the nineteenth and twentieth centuries now require renovation. During rehabilitation, the question arises of how to preserve built heritage while fulfilling modern standards on safety and structural integrity. In a traditional recalculation, the glass panels are considered to be dead load on the iron frame, leading to the conclusion that the original frame requires strengthening. This paper presents a calculation that takes the contribution of the glass plates into account while assessing historical glass coverings. The overall structural behaviour of the iron and glass roof of the Saint-Hubertus Galleries, Belgium, was simulated and a parameter study was performed using a finite-element software package. The original structure comprises a wrought-iron frame clad with single glass panes connected to the glazing bars with traditional linseed-oil putty. The behaviour of the original structure, the influence of the application of modern adhesives and sealants, and the replacement of single with laminated glass plates is investigated. Although building such models is time consuming, including glass panes in the model leads to lower stresses, deflections and a better buckling behaviour, even if connected with linseed-oil putty.

Laminated altered layers in historical glass: Density variations of silica nanoparticle random packings as explanation for the observed lamellae

One of the most striking but unexplained phenomena in the natural degradation of glass is the transformation of an almost colorless, transparent and homogeneous glass into a colored, opaque and heterogeneous degradation layer. In many cases, the degradation layer consists of numerous lamellae with a thickness between 0.1 and 10μm. However, both internal structure and formation process of laminated degradation layers remain unclear. In this paper, a model is proposed where we assume that transformed (degraded) glass consists of a random packing of nano-sized silica particles while the lamellae are the result of different packing densities. The model is able to connect the texture of numerous lamellae observed by several types of microscopic techniques with the structure at molecular level determined by means of chemical analysis. In addition, the model is able to explain numerous properties such as the parameters responsible for the contrast between lamellae. This contrast can be caused by differences in color, density, elemental composition, or surface roughness.

OctTES/TEOS system for hybrid coatings: real-time monitoring of the hydrolysis and condensation by Raman spectroscopy

The hybrid organic–inorganic system Tetra-ethyl-ortho-silicate functionalized with Octyl-triethoxy-silane, studied as protective coating for the preservation of historical glasses from the environmental weathering agents, has been characterized by Raman spectroscopy by monitoring the sol-gel reactions over time through characteristic features in the spectrum. In particular, for the hydrolysis reaction the disappearance of the 653 cm−1 (Si-O symmetric breathing) and 810 cm−1 (CH2 rocking in Si-alkoxides) peaks and the growth of the 710 cm−1 band, because of hydrolyzed alkyl-silane, and of the 881 cm−1 peak (ethanol C–C symmetric stretching) have been checked. Moreover, the condensation reaction can be tracked by the disappearance of the two main peaks of the alcohols at 816 and 881 cm−1, going along with the growth of the broad band between 250 and 500 cm−1 (Si–O–Si symmetric bending) and of the feature at 840 cm−1 (Si–O–Si stretching). At the end of the condensation process the Raman spectrum still displays spectral bands unique to the alkyl chain in Octyl-triethoxy-silane, in the 1330–1450 cm−1 and 2725–3000 cm−1 ranges. Copyright © 2016 John Wiley & Sons, Ltd.

Iridescence in Ancient Glass: A Morphological and Chemical Investigation

Visible damage on the surface of historic glass, iridescence, is developed by the influence of environmental factors during time. Iridescence is usually considered as an age indicator in historic glass. Samples from the ancient Sasanian historic site called “Tomb‐e Pargan” in the Boushehr Province of Iran were subjected to microscopic analyzing with ESEM, ICP‐OES, and polarization microscopy to characterize structural damages and its impact on the surface deposition. Chemical–mineralogical studies were also performed. The current investigation suggests that the iridescent layer is developed as the result of alkali ion depletion on the glass surface following the formation of a shelly layer. Due to the porosity of ancient glass surface, ions migrate and deposit continuously on the surface in the form of crust. The phenomenon causes fine lamellar structure on the surface. Samples from Tomb‐e Pargan characteristically contain potassium and magnesium.

Spectroscopic Investigation of the Coloration and Fabrication Conditions of Medieval Blue Glasses

Potash‐ and soda‐lime‐stained glasses from the 12th–13th centuries, blue‐colored by cobalt, have been investigated by Mn, Fe, and Cu K‐edge X‐ray and optical absorption spectroscopies in order to determine the oxidation state of these elements and their impact on the blue color. Remelting these historical glasses in air at 1200°C, the estimated temperature of medieval furnaces, revealed that these four glasses are more reduced before remelting. This favors Mn as weakly absorbing Mn2+, Fe as Fe2+ and Cu as colorless Cu+. Therefore Fe2+ is the second blue chromophore and copper was not intentionally used by glassmakers to obtain a blue color. A colorimetric analysis indicates that these specific melting conditions have a limited effect on the blue color of these glasses. Based on the spectroscopic determination of the redox state of Fe, Mn, and Cu, we estimate the oxygen partial pressure in medieval furnaces to be 10−7–10−9 and 10−5 bar for the potash‐ and soda‐lime samples, respectively. The comparison with previous results enables to prove the evolution of furnace technology over centuries.

Toward a Raman/FORS discrimination between Art Nouveau and contemporary stained glasses from CdSxSe1 − x nanoparticles signatures

CdSxSe1 − x quantum dots received considerable attention in academic studies and as cut‐off filters and indirect‐gap semiconductors. These later compounds have also been used for artistic purposes to produce colored glass since the 1920s thanks to their bright colors. Because non‐invasive conditions are now mandatory when considering objects belonging to the cultural heritage, the use of Raman and fiber optics reflectance spectroscopy has been identified as potential ones to obtain information about the nanostructure of six samples of historical glass produced between the late 1920s and modern days. The average elemental composition of the nanocrystals has been deduced processing both optical and vibrational data, and the result arising has been compared taking into account the several factors affecting the experimental results. The diffusion of zinc inside the nanocrystals has also been questioned by the shift caused on the CdS‐ and CdSe‐like phonon band wavenumber and on the absorption edge wavelength. An investigation of the size distribution and crystallinity of CdSxSe1 − x nanoparticles has been also performed considering those parameters that are mainly influenced by the disorder of the system, such as the extent of the Urbach tail and the Raman bandwidth. Thanks to the results obtained, discrimination between the more recent glass and the older Art Nouveau ones has been verified, leading to the identification of a useful analytical protocol for conservation purposes. Copyright © 2015 John Wiley & Sons, Ltd.