Colorless Glass Research Articles

Glass-forming compositions and physicochemical properties of degradable phosphate and silver-doped phosphate glasses in the P2O5–CaO–Na2O–Ag2O system

Phosphate and silver-doped phosphate glasses are potential candidates for use as degradable biomaterials and as antibacterial materials as well. The present investigation explores the glass-forming compositions (GFC), physical properties and degradation rates of both phosphate glasses in the P2O5–CaO–Na2O ternary system and silver-phosphate glasses derived from it by introducing Ag2O in replacement of Na2O. The glasses were prepared using the traditional melting–annealing technique applied in glass making industry. Bulk glasses were prepared without using any special precautions or specific conditions (contrary to previous studies) which can prevent crystallization or segregation of silver particles from the melt. A wide glass formation domain with ≥40mol% P2O5 was determined in the ternary P2O5–CaO–Na2O system. However, up on Ag2O addition, the amount of Ag2O that can exist in the glass and remains amorphous was limited to 2mol% as ensured from X-ray diffraction (XRD). The compositions with ≥60mol% P2O5 and 0.5, 1 or 2mol% Ag2O formed transparent and colorless silver phosphate glasses. Whereas, the compositions with ≤55mol% P2O5 did not form glasses and showed immediate partial crystallization and separation of silver particles. Thereafter, the structure of representative glasses was studied by FT-IR and UV–vis absorption spectroscopy. Finally, as silver ions function as antibacterial metal ions, the amounts of silver ions released from silver phosphate glasses were measured by atomic absorption spectrometry (AAS).

On the making, mixing and trading of glass from the Roman military fort at Oudenburg (Belgium)

This paper presents the analysis of decoloured and naturally coloured glass from well-dated contexts in the southwest corner of the Roman fort at Oudenburg (Belgium) ranging from the late second to the early fifth century AD. The aim is three-fold. First, provide comparative material in the study of glass consumption from the northwestern provinces of the Roman Empire. Secondly, evaluate possible diachronic shifts in the applied decolourizing agent to produce colourless glass as to assess potential correlations between glass production recipes, provenance and chrono-typology. Finally, provide an added value to the research of glass recycling and mixing in the Roman imperial period. Nine subgroups are distinguished based on their chemical composition determined by LA-ICP-MS: Sb-only, two groups of Mn-only, four groups of mixed Mn-Sb, HIMT and one glass without any decolouring agent. The Sb-decoloured glass is used in the earliest phases and can be attributed to an Egyptian provenance. The two subgroups of Mn-glass likely come from different provenances: one from Egypt and the other later one from the Levant. Most of the glass shows high marks of mixing based on high trace elements concentrations and the simultaneous presence of antimony and manganese. Inhomogeneous mixing of manganese and antimony was also detected through μXRF. One Mn-Sb subgroup likely comes from mixing antimony glass with HIMT. The obtained results help better recognise the shifts in applied glass recipes throughout the Roman imperial period and improve our understanding about the mixing and recycling of glass to supply a Roman military camp.

Crystallization control toward colorless cerium-doped scintillating glass.

The construction of cerium-doped materials is of great technological importance for various applications, including smart lighting, biological shielding and high-energy ray and particle detection. A major challenge is the efficient prevention of the undesired colorization after cerium doping. Here we present the nanocrystallization method for constructing colorless cerium-doped glass with extremely high cerium concentration (15 mol%). The structure and optical characterizations confirm that the notable color change of glass is associated with the precipitation of CeF3 crystalline phase during heat-treatment. The chemical state investigation shows that most of cerium ions exist in the form of Ce3+ in both the glass and glass-ceramic samples. The chemical environment study indicates a dramatic change in the local structure unit from -Ce-O- to -Ce-F-, which is believed to dominate the decoloring phenomenon in cerium doped glass. As a result, a significant improvement in the ultraviolet excited luminescence (~35 times enhancement in intensity) and scintillating performance can be achieved, pointing to potential applications in X-ray detection.

Ancient glassware travelled the Silk Road: Nondestructive X-ray fluorescence analysis of a fragment of a facet-cut glass vessel collected at Kamigamo Shrine in Kyoto, Japan

In 1964, a fragment of a colorless facet-cut glass vessel was collected at the Kamigamo Shrine, located in Kyoto, which was the capital city of Japan from late 8th century AD through the mid-19th century AD. X-ray fluorescence analytical techniques were applied to this fragment in a nondestructive manner with the aim of scientific provenancing based on its chemical compositional features. It was found that, the chemical composition of the fragment closely matched that of one compositional group in Sasanian glass which was characterized by the use of a pure silica source and magnesia-rich plant ash as the raw materials. Given the discoveries of facet-cut glassware from the region of the Sasanian Empire that are very similar to this fragment, it is concluded that the primary production and possibly subsequent production processes (i.e., secondary production and a facet-cut decoration) of this glass were carried out at the Sasanian glass workshops. This study is the second case of an investigation that has identified a specific provenance of one of the few glass vessels introduced into ancient Japan through the Silk Road.

Study of Radiation-Induced Processes in Electron-Irradiated Alkali-Silicate Glass

The formation of a localized charge upon irradiation of colorless silicate glass containing Na, K, and Ba is investigated. Irradiation is performed in the sterilizing mode in air at room temperature using an Elektronika U-003 electron accelerator (average power 4 MeV). The integral fluence is accumulated in 6 stages of sequential irradiation from 1.8 × 1013 to 1.8 × 1015 e/cm2, which corresponds to exposure doses ranging from 0.3 to 30 MR. The irradiation creates a permanent dark brown coloration of the glass, which protects the medicinal products from sunlight. The absorption spectra demonstrates a red shift of the absorption edge from 300 to 500 nm depending on the accumulated exposure dose, which is typical for charged metal-containing nanoparticles of 20 to 30 nm.

The effect of replaced recycled glass on thermal conductivity and compression properties of cement

This study deal with recycling of waste colorless glass bottles which are prepared as a powder and use them as an alternative for cement to save the environment from west and reduce some of cement(ceramic) damage and interactions with conserving physical properties of block concrete. Different weight percentage (0%, 2%, 4%, 5%, 6%, 8%, 10%, 15%, 20% and 25%) of recycled glass bottle were use in this research to be replaced by a certain percentages of cement. Thermal conductivity was studied for prepared samples. Results show that the thermal conductivity decrease with the increase of weight percentage of glass powder comparing with the stander sample.

Preparation of colourless phosphate glass by stabilising higher Fe[II] in microwave heating

Iron impurity in raw material remains a major challenge in producing colourless glass. In this investigation, we report microwave (MW) heating capable of altering Fe-redox ratio (Fe2+/∑Fe) enabling preparation of colourless phosphate glass. The effect of Sn concentration in retention of Fe[II] in glass melted in MW was compared with conventional glasses. Colourimetric study developing Fe2+-ferrozine colour complex reveals Fe-redox ratio ≥0.49 required to obtain colourless phosphate glass. In microwave heating, addition of 1 wt.% Sn metal powder can impart the desired effect whereas addition of 1.9 wt.% Sn metal powder is required in conventional heating. The correlation equation of Fe-redox ratio with concentration of Sn metal is found to be different in microwave and conventional heating. Thus, exploiting this different redox changes in MW heating optical properties can be tailored. Preservation of higher Fe[II] in MW melted glass is also confirmed by XPS and TGA. 31P MAS NMR spectra suggest that transition from cross linked ultra phosphate to linear polymer metaphosphate network in incorporation of Sn is found different in glass prepared adopting microwave irradiation. 27A1 MAS NMR spectra suggest higher relative content of Al6+ in glass obtained from MW heating. Energy consumption analysis revels 3.4 kWh in MW heating while 14 kWh in conventional glass melting using resistance heating. Further, glass melting in MW can be completed within 2 h unlike ~5 h needed in conventional. MW heating plays a significant role in improving properties to make colourless phosphate glass in addition to significant energy and time saving.

Wearing Colored Glasses can Influence Exercise Performance and Testosterone concentration?

Perception of red color is associated with higher testosterone concentration and better human performance. Thus, we evaluated the acute effects of wearing colored-lens glasses on the YoYo intermittent endurance exercise test 2 (YoYoIE2) performance indicators and testosterone concentration. Ten soccer players performed three YoYoIE2 (counterbalanced crossover) wearing colorless (control), blue- or red-lensed glasses (2–4 days of rest in between). YoYoIE2 performance did not differ among the trials ( p >0.05), but blood testosterone increased post-exercise in red compared to red baseline (red=14%, effect size=0.75). Analysis showed faster heart rate recovery ( p <0.05) at 1 min post-test for blue compared to red lenses. Rating of perceived exertion and blood lactate concentration did not differ ( p >0.05) among the trials. Wearing red-colored lenses during high-intensity intermittent exercise increased testosterone concentration, but do not influence performance.

Clarity and brilliance: antimony in colourless natron glass explored using Roman glass found in Britain

This paper discusses the development of Roman antimony decolourised natron glass, its dominance, and subsequent decline, using new trace element data for colourless glass found in Britain. Experimental glasses are used to investigate the influence of different proportions of raw materials (particularly the ratio of natron to calcium carbonate) on the resulting transparency or opacity of glass when antimony is added. Focusing on the 1st to 3rd centuries AD, the study has found that (1) There are chronological differences in antimony colourless glass compositions including (a) some early vessels have abnormally low calcium, aluminium and barium levels; (b) 1st/mid-2nd-century AD vessels in Britain may also contain up to 0.6 wt% lead oxide whereas mid-2nd/3rd-century AD vessels contain less than 300 ppm, and (c) the antimony content tends to decline over time. (2) These developments can be linked to production and recycling practices; but trace elements suggest that all of these antimony colourless glasses share an origin, probably Egypt. (3) Crucially, production of experimental glasses illustrates the inherent suitability of a sodium-rich, calcium-poor base glass composition for making antimony colourless glass, as it readily dissolves added antimony; conversely lower-sodium, higher-calcium glasses start to form opacifying calcium-antimonate crystals with the same quantities of antimony. Thus, the sodium-rich, calcium-poor glass composition from Egypt was ideally suited for decolourising with antimony and formed a water-clear glass. The calcium-rich Syro-Palestine glasses were more easily opacified with antimony to make opaque glass, but were decolourised with manganese, not antimony.

ФАКТОРЫ, ВЛИЯЮЩИЕ НА ИНТЕНСИВНОСТЬ ВЫЩЕЛАЧИВАНИЯ ТАРНОГО ОБЕСЦВЕЧЕННОГО СТЕКЛА ФТОРХЛОРСОДЕРЖАЩИМИ ГАЗООБРАЗНЫМИ РЕАГЕНТАМИ

The aim of the undertaken experiments was to determine the factors affecting the process of dealkalization of container colorless glass with fluorine–and chlorine–containing gaseous reagents.The subjects of investigation were various types containers (bottles, jars and flasks) of colorless glass. Hydrogen chloride, difluorodichloro-methane and difluorochloromethane and mixtures of these reagents with sulfur dioxide were used for the chemical treatment of glass. We have investigated the influence of the following factors on the process of dealkalization of container colorless glass with fluorine–and chlorine–containing reagents: temperature, chemical compositions of the gas medium, duration of the thermochemical treatment, concentration and humidity of gaseous reagent, re-peated thermal treatment and surface state of the samples

Quaternary volcanic ash of Kharkiv region

Formulation of the problem. The article is devoted to detail geological and mineralogical description of quaternary volcanic ash in Kharkiv region. The purpose of the article is to ground its origin. Presentation of the main material. Quaternary volcanic ash was discovered in Kharkiv region in the middle of last century. There are a few Late Neo-Pleistocene deposits of volcanic ash in Kharkiv region now. They are located in Kharkiv and near such villages as Russki Tishki, Novoselivka, Levkivka, Donetzke and Krasnokutsk. Such deposits of volcanic ash were found in the neighboring regions of the Eastern Ukraine - Lugansk, Donetsk, Dnieperpetrovsk and some other regions. Volcanic ash forms the elongated lenticular deposits in the loess loam strata. The contact of ash beds is clear with underlying loess and gradual with overlying loess. The ash lies 3-5 m below the surface of loess. These ashes are light-grey with feeble yellow or brown shades. Its thickness is up to 0.4 m. The particles of the ash are volcanic colourless isotropic glass with refraction index 1,517. Its forms are various. Plate isometric and elongated ash particles with even straight or cambered sides are the most widespread. Predominance of 0.005-0.1 mm particles in this ash rocks is confirmed by the results of mechanical analyses. This tephra is badly sorted. Their sort factor is 4.2-5.9. The ash deposits were formed by wind transportation of ash particles to wind shadow zones. The results of X-ray investigation are typical for glass. IR-spectra investigation revealed molecular water and hydroxyl groups in the volcanic ash. Chemical composition of the volcanic ash of Kharkiv region is characterized by the average percentage of SiO2 – 58.88, Al2O3 – 18.79, Na2O – 5.03, K2O – 6.30, Na2O+K2O – 11.33. Relation of Na2O to K2O is 0.80 and Na2O+K2O to Al2O3 is 0.60. It corresponds to trachyte and phonolite and is confirmed by the refraction index of glass particles. The volcanic glass particles are angular and non-rounded. This fact signifies the eolian origin of ash deposits. Moreover, numerous manifestations of volcanic ash scattered in loess loams are found in Kharkiv region. These loams contain only a few per cents of poorly rounded volcanic ash particles. The loess loams with scattered volcanic ash and volcanic ash deposits belong to the same stratigraphic datum - to the Bugskij horizon, which correspond to Wurmian stage. Conclusions. All tephra deposits of Kharkiv region are in the ash plume of the super-eruption, which occurred in Southern Italy about 39280 years ago (Campanian Ignimbrite eruption). Kharkiv objects fill territory in this plume between the ash depositions of Romania and Russian Voronezh region. They are similar to all other tephra localities of this plume. The volcanic ash was taken by air from the Phlegraean Fields though the distance between Kharkiv and this volcano is over 2000 km. Scientific novelty and practical significance. We can affirm that Kharkiv ash deposits are the result of distant ashfall of Phlegraean Fields super-eruption. The volcanic ash is a horizon marker in the Neo-Pleistocene strata and a datum mark for archaeological study of the Paleolithic cultures. Volcanic ash is a remarkable component of Kharkiv region geological monuments. Russki Tishki locality of volcanic ash is the best object in Kharkiv region. It is situated in 22 km north from Kharkiv. These geological sights have been used as objects of scientific tourism and native land study. Their protection is of highly necessity.

Mellow yellow: An experiment in amber

Amber natron glasses were produced from at least the Hellenistic period and continued to be produced into the early second century CE. However, as with other strong colours used for Roman vessel production, this colour gradually declined in popularity as colourless and blue-green glass came to dominate. Whilst the colouring mechanisms for blue-green glasses are relatively well understood, the cause of the distinctive amber colour is more complex and can be attributed to the iron sulphur chromophore. This paper demonstrates, using analytical data and model glasses, that the amber colour develops during primary production, and that the sulphate-rich natron is key. The analytical data show that most natron amber glass was probably produced in the Levant alongside the more common blue-green glasses, however, its composition is different. Whilst many glass colours were made in a secondary stage, by adding colourants and opacifiers to a blue-green or colourless glass base, amber glass was not made this way since it required a slightly different set of raw materials and melting technologies. These findings suggest that the production of the glass required specialist knowledge, and particularly skilled furnace operation, in order to produce repeatable results. Skilled specialists would also be required to work amber glass whilst retaining the same clear amber hue, especially for complex wares, such as mosaic vessels, where the glass would be reheated more than once.

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Evaluation of Akaibiri Creek Sand at Akaibiri Town and Environments, Central Niger Delta, Nigeria, for Industrial Applications

The colours of fifteen shallow dept non-weathered field samples of Akaibiri creek sand at Akaibiri Town and environments collected for physical and chemical properties investigation in the laboratory using BS:2975: 1958/1988 standards specifications were bright yellow, brown, reddish-brown, white and dark grey. The physical sieve grade size distribution was 2mm(3.0%), 1mm(6.11%), 500µm(13.88%), 300µm(54.25%), 180µm(9.33%), l06µm(7.14%), 63µm(2.87%), and <63µm(1.37%). The grade size analysis result indicated that the sand was of medium grade. The physical properties combined with a moisture content of 7.3% presented the sand as a material suitable for use in the construction, transport, building, refractory and sanitary industries as aggregates, but not for any type of glassmaking except processed for use in making general glass. The X-ray Fluorescence (XRF) analysis Geochemical composition was SiO 2 (92.50%), CaO(0.355%), MnO(0.018%), Fe 2 O 3 (1.00%), TiO 2 (0.91%), Na 2 O(0.09%), K 2 O(2.26%) and L. O. I.(0.35%). This composition is representative of the sand. The most important industrial use determining elements in the sand were the Silica (Si), Iron (Fe), K 2 O (K) and Titanium (Ti). The Silica (SiO 2 ) content of 92.50%, was low and the sand cannot be used as it is, for glass making. The iron (Fe 2 O 3 ) content (1.00%), Ti (0.91%), K (2.26% ), Na (0.09%) and even the L.O.I (0.35%) were too high for making any type of glass. The sand was generally not suitable for glass making particularly, o f colourless glass based on the geochemical properties and loss on ignition. The non-detection of Alumina (Al) in the sand suggests its suitability for use in the manufacture of common glass and the presence of high content of colouring agents Ti and Fe suggests the suitability for coloured glass making. The contents of Si and K, (92.50% and 2.26%) respectively and the non detection of Al, can make the sand also suitable for use in the refractory and sanitaryware industries.

Colourless Roman glass from the Zadar necropolis: An exploratory approach

This paper presents the study of eighteen samples of colourless glass dated to the Roman period (1st to 3rd centuries C.E.) and that were unearthed in Zadar, Croatia. In this exploratory research, the chemical composition of the glass, which was determined by μ-PIXE, was divided into two main groups based on the alkali and alkali-earth contents: glass with low CaO and Al2O3, and high Na2O contents (Group 1), and glass with high CaO, Al2O3, and low Na2O contents (Group 2). The chemical composition from Group 1 is related to polygonal bottles and the composition from Group 2 to bell-shaped bottles, the latter being considered of local provenance. The analysis of MnO, Sb2O5 and Al2O3 contents and ratios suggests that only three samples from Group 1 were obtained from a primary glass source discoloured with Sb and the remaining fragments are the result of recycling activities, whereas all fragments from Group 2 were made using a different primary glass source discoloured with Mn. Finally, considering all the compositional characteristics of the analysed glass, it is proposed that the primary glass source of Group 1 was Egypt, and that glass from Group 2 came from the Levant region.

Provenance studies of 18th century potassium-rich archaeological glass from Portugal

The archaeometric study of a group of colourless glass fragments recovered from two archaeological excavations performed in Lisbon, Portugal is here reported. The archaeological interventions were performed at Rua do Arsenal (LRA), where the ruins of the Côrte-Real Palace were partially discovered, and at the Roman Theatre Museum (LTR), where the remains of a middle-class house dated to the 18th century were found. The recovered glass fragments are dated between the end of the 17th century and the 18th century, and were chemically characterised with the aim of discussing its provenance. Micro particle induced X-ray emission (μ-PIXE) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) were the chosen analytical methods to characterise the glass composition. All twenty-five fragments proved to be of a potassium-rich composition, where the choice of raw materials seems to have been made with extreme care. This is reflected in general by a composition with low levels of impurities, such as alumina and iron oxide, and high levels of silica.Two compositional groups were identified, that besides differing in other components have different contents of arsenic oxide. None of the groups could be undoubtedly compared with the few known potassium-rich compositions from coeval glass production centres in Europe. The majority of the analysed samples could only be compared, in terms of major oxides, with the potassium-rich production from the Coina Glass Factory in Portugal.

Allegories of Creation: Glassmaking, Forests, and Fertility in Webster’sThe Duchess of Malfi

Allegories of Creation: Glassmaking, Forests, and Fertility in Webster’s<i>The Duchess of Malfi</i>

Phosphate: a neglected argument in studies of ancient glass technology

The phosphate content of ancient alkali-glass has been tested as an indicator for biogenic ash, used in glass production. The living tissue of plants and vertebrates accumulates phosphate that remains in native ash as a main component (1 to over 10 wt%) forming together with biologically essential element oxides a complex chemical fingerprint that characterises any glass made with it. If, instead of native plant ash its alkali extract is used, soluble oxides are concentrated in the extract whilst insoluble oxides get depleted, leading to a different elemental fingerprint of the glass. Geogenic raw-materials for glass production like quartz-rich sand, evaporitic natron, or limestone are virtually phosphate free (below detection limit up to ≈0.15 wt%). Several collections of ancient glass stemming from different archaeological excavations, regions and times have been analysed by instrumental methods (WD-XFA, ED-XFA, thermal techniques), i.e. flat- and hollow K–Ca glass dated 1699/1714 N = 340, Na–Ca glass 13th/14th cy N = 94, Na–Ca glass 7th/9th cy N = 110, and alkali-Ca glass La Tene N = 395. Although the phosphate content of native alkali plant ash gets diluted with quartz sand by a factor of roughly two in glass production, it remains a main component of the product glass. Wood-ash glass contains 1–3 wt% phosphate, whilst glass manufactured from halophyte ash contains around 0.2–1 wt%. When processed wood-ash is used, the phosphate content in glass sinks below 1 wt%, the depletion factor amounting to roughly 8–15. Glass made from evaporitic soda displays phosphate contents below 0.2 wt% in the cases examined. The phosphate content of ancient alkali glass thus indicates whether virtually phosphate-free evaporitic soda has been used as a flux, or native ash of halophile plants. Ternary melting diagrams reveal at least three groups of alkali glass: Naturally coloured forest glass displays a broad distributional pattern with minimum melting temperatures ranging from 1200 to ≥1450 °C, colourless potash-extract glass from 900 to ≈1200 °C, and the typical, tight cluster of Roman sodium-calcium glass ranges from 800 to ≈900 °C. The wide-spread sodium-lime glass made with native halophytic ash, contains besides Na2O as the chemical main component always some K2O, and melting temperatures range from 800 to ≈1000 °C.

Durability of Mortar Made with Fine Glass Powdered Particles

Different studies investigate the use of waste glass in Portland cement compounds, either as aggregates or as supplementary cementitious materials. Nevertheless, it seems that there is no consensus about the influence of particle color and size on the behavior of the compounds. This study addresses the influence of cement replacement by 10 and 20% of the colorless and amber soda-lime glass particles sized around 9.5 μm on the performance of Portland cement mortars. Results revealed that the partial replacement of cement could contribute to the production of durable mortars in relation to the inhibition of the alkali-aggregate reaction. This effect was more marked with 20% replacement using amber glass. Samples containing glass microparticles were more resistant to corrosion, in particular those made of colorless glass. The use of colorless and amber glass microparticles promoted a reduction in wear resistance.

Provenance of polychrome and colourless 8th–4th century BC glass from Pieria, Greece: A chemical and isotopic approach

Glass objects from Pydna and Methoni in modern-day Greece, dated to the eighth to fourth century BC, were chemically investigated. The combined use of multiple analytical techniques allowed the elemental and isotopic characterization of these polychrome and colourless glass artefacts in order to examine their provenance. All fragments were found to be soda-lime-silica natron-based glass produced from a rather pure silica-rich sand containing sea shells, and mixed with natron possibly coming from more than one source. Based on the strontium and neodymium isotopic signatures, most glass artefacts likely derive from a Syro-Palestinian production site although the exact location is unknown. Also the oxygen isotopic signature of most of the samples suggests the manufacturing of the artefacts from raw materials with a primary origin along the Syro-Palestinian coast. Nevertheless, the use of particular raw materials cannot be excluded for some artefacts, as some samples show enriched δ18O values pointing to a different glassmaking tradition.