Coloured Glasses Research Articles

Baubles, bangles and beads: Recycling coloured glasses in the British Iron Age and Roman periods

AbstractCompositional analysis has proved to be a powerful tool for investigating the recycling of transparent glass in the Roman and Byzantine periods. This paper expands the focus further to explore the recycling of coloured and opaque glass in the Late Iron Age and Roman periods in Britain. A review of the findings to date, predominantly for beads and bangles, illustrates how a combination of methods is needed to identify when coloured glass has been recycled and altered in the past. Chemical analysis, microstructural examination and experimentation have been used to understand how coloured glass was mixed, diluted, and modified with novel colourants and opacifiers, in ways that are not apparent from non‐destructive chemical analysis alone. The paper discusses the possible types and sources of trade glass, the challenges of recycling mono‐ and polychrome glass in different colours, and the unconventional methods used by glassworkers on the periphery of Roman influence to extend and modify coloured glass to produce distinctive items in order to express their identity.

‘Left Pessimists’ in ‘Rose Coloured Glasses’? Reflections on the Political Economy of Socio‐Legal Studies and (Legal) Academic Well‐Being

AbstractThis article reflects on the significance of the Journal of Law and Society and critical socio‐legal work in the context of changes in the political economy of universities and socio‐legal studies. It interweaves an analysis of this shifting political economy with consideration of another topic, namely, academic well‐being and mental health, especially in this moment, to demonstrate the continuing pertinence and importance of the left critique of universities. Well‐being has become part of a far broader set of counter‐narratives to neoliberalism evident in attempts to reposition it as a ‘force of change’, to develop new ways of working that might challenge traditional work cultures and organizational structures, and to resist the marketized neoliberal university and re‐envision what a ‘good university’ might be. Rejecting the criticism of ‘left pessimists’ in ‘rose coloured glasses’, I make the case for the continuing significance of engaging in public education and research as a public good.

(Re)-wiring a brain with light: Clinical and visual processing findings after application of specific coloured glasses in patients with symptoms of a visual processing disorder (CVPD): Challenge of a possible new perspective?

The present investigation examined whether changes of electrophysiological late event related potential pattern could be used to reflect clinical changes from therapeutic intervention with coloured glasses in a group of patients with symptoms of central visual processing disorder. Subjects consisted of 13 patients with average age 16years (range 6–51years) with attention problems and learning disability, respectively. These patients were provided with specified coloured glasses which were required to be used during day time. Results indicated that specified coloured glasses significantly improved attention performance. Furthermore electrophysiological parameters revealed a significant change in the late event related potential distribution pattern (latency, amplitudes). This reflects a synchronization of together firing wired neural assemblies responsible for visual processing, suggesting an accelerated neuromaturation process when using coloured glasses.Our results suggest that the visual event related potentials measures are sensitive to changes in clinical development of patients with deficits of visual processing wearing appropriate coloured glasses. It will be discussed whether such a device might be useful for a clinical improvement of distraction symptoms caused by visual processing deficits. A model is presented explaining these effects by inducing the respiratory chain of the mitochondria such increasing the low energy levels of ATP of our patients.

Isotopic analysis of antimony using multi-collector ICP-mass spectrometry for provenance determination of Roman glass

Based on promising results obtained in earlier work on antimony ores, we have investigated the use of natural variation in the isotopic composition of Sb as determined using multi-collector ICP-mass spectrometry (MC-ICP-MS) for provenancing Roman glasses. In antiquity, Sb was used either as a decolourizer or as an opacifier and thus, colourless and opaque coloured glasses from different regions and periods were selected for investigation. Both, the sample digestion and isolation of Sb preceeding isotopic analysis via MC-ICP-MS have been optimized and validated for this type of materials. For this purpose, NIST SRM 610 glass reference material and an in-house standard were employed. Isotope ratio determinations were carried out by MC-ICP-MS, relying on In as an internal standard for correction for instrumental mass discrimination. The merits of external calibration in a sample-standard bracketing approach and the so-called “revised Russell's law” for mass bias correction were compared, with the latter providing higher precision and better reproducibility. The 123Sb/121Sb isotope ratio in glass could be determined with a reproducibility (or external precision) of ca. 0.4ε, while in Roman colourless and Hellenistic opaque glass samples, a variation of 3 to 4ε units was found. The results seem to suggest the use of similar Sb sources for both types of glasses, and the existence of at least two different Sb sources for glass production in the Roman era.

Nano Rods for Coloured Glasses Obtained by Hybrid Sol–Gel Coating

Many new materials are now allowing new properties thanks to nanotechnology because this domain of physics gives possibilities to optimize targeted properties even if these materials react in very various influential parameters. Architectural, automotive, bone pathologies, environment, display applications are some concerned domains. The sol-gel process is a method allowing the realisation of coats at ambiant temperature, thus it is possible to realize Liquid Crystal Display (LCD), water-repellent coatings on privacy glass, antireflective coatings, hydrophobic or hydrophilic surfaces, bone tissue regeneration. In this study, the purpose is to show the thermal influence on a covered glass with a complex hybrid sol-gel solution. This coated glass is going to change color from red to orange under the heat influence. This color change effect comes from the evolution of various compounds organizations then/or from their loss during the degassing sequence. We show in spite of the complexity of the process that the responsible is mainly the organic dye. Thus the structure of the heated glass at 250 degrees C looks radically different than the heated one at 350 degrees C. SEM measurement allows to identify the surface compositions and to determine the elementary composition along the sample's cross section. TGA is used to justify a mass loss when samples are annealed. UV/Visible measurement is realized by two methods: in-line transmission to evaluate luminous flux and thus give colorimetric dot in the normalized CIE diagram and diffuse transmission to observe the size influence of the pigments. Infrared Reflectivity allows to evaluate the influence of species on the structure and to better target the nature of the lost compounds during annealing. TEM measurement proves that the obtained iron particles are nano rods for both samples.

The effect of silicate network modifiers on colour and electron spectra of transition metal ions

Coloured silicate glasses of Li 2O–SiO 2, Na 2O–SiO 2 and K 2O–SiO 2 systems were produced by melting at 1400 °C. As dyes, compounds of cobalt, nickel, chromium and manganese were used. The aim of this study was to determine the effect of glass matrix modifiers on colour and d–d electron spectra of chosen transition metal ions. From the analysis of colour and electron spectra of the obtained glasses it follows that the chemical composition of the glass matrix influences the coordination state as well as the oxidation state of the transition metal. Cobalt and nickel occur in examined glasses as divalent ions (Co 2+, Ni 2+) in both coordinations – octahedral and tetrahedral. A decrease of the electronegativity of modifiers (Li → Na → K) and an increase of the glass matrix basicity promotes the tetrahedral coordination of cobalt and nickel. Chromium and manganese occur in silicate glasses in various oxidation state, though Cr 3+ and Mn 3+ ions in octahedral coordination are dominant. The decrease of the electronegativity of the modifiers causes a shift of oxidation/reduction equilibrium towards higher valence of the transition metals (Cr 6+, Mn 3+).

Disproportionation of Qm (0 ≤ m ≤ 4) species in partially devitrified Li2Si2O5 glasses with small amounts of P2O5

The effect of addition of small amounts of P2O5 in the lithium disilicate glasses results in the scavenging of lithium metal ions by a phosphate group, Li3PO4. As a consequence of the scavenging, the silicate network partially repolymerises. The phosphate group remains intact during heat treatment of the optically clear, X-ray amorphous and slightly nucleated base glasses. However, the relative amounts of the silicate species, Qm (0 ≤ m ≤ 4), are dependent on the state of the glasses. These amounts, in the optically clear and X-ray amorphous, do not change with heat treatment but they do change, i.e. disproportionation occurs in the slightly nucleated and milky coloured glasses. The disproportionation follows the relation 2Q3 → Q2 + Q4 which is evident from the relative intensity of the different peaks.

Preparation of Coloured Glasses with Nanosized Secondary Phases via Sintering of Colloidal Gels

Preparation of Coloured Glasses with Nanosized Secondary Phases via Sintering of Colloidal Gels

Coloured glasses in selenite systems

Etude de la preparation de verres colores en introduisant SeO 2 dans les systemes selenie-tellurite contenant des oxydes tels que V 2 O 5 ou MoO 3

Coloured glasses and colour vision, with reference to car driving.

Coloured glasses and colour vision, with reference to car driving.

Spectrophotometric Study of Coloured Glasses (1)

A systematic study of the colour of glasses containing iron, and both iron and manganese was carried out using the spectrophotometric method.The base glass was a soda-lime-silica type, and the colouring agents added to the batch were rouge, copper slag, manganese dioxide, and manganese ore, all being the technical grade. Twenty four smaples containing different amount of colouring agents were subjected to the investigation. The transmission between 350 and 1100mμ were measured by a photo-electric spectrometer to represent the result by C. I. E. colour specification using mainly the chromaticy coordinates and the lightness which is familiar to glass technologists as luminous transmission.With increasing content of total iron oxide the colour of glasses added with rouge was observed to change from blue to green.If the partial pressure of oxygen is kept constant in the melting processes the relation[FeO]2/[Fe2O3]=k/[O2]1/2=α(constant)would hold, so that the ratio FeO/Fe2O3 is reduced with increasing amount of iron oxide. This means that the yellowish green tint of Fe2O3 would become stronger than the blue tint of FeO.FeO makes the glasses darker nine times as much as Fe2O3, so that a glass containing FeO which is equal to 1/9 of Fe2O3 gives the same luminous transmission.It was confirmed that the luminous transmission is linearly related withe FeO content of glass estimated by direct chemical analysis. This gives the possibility of estimating directly the value of FeO and Fe2O3 with fairly high accuracy by measuring the transmittance at a characteristic wave length. It was proved that this method may be applied to the iron contents of 0.5-2.5wt% Fe2O3.The colour of the glasses added with both iron and manganese changes mainly with the change of the ratio of mangenese to iron. The transmittance curves were classified into three groups, and the authors have advanced the three chemical equations which explain satisf actly the existence of the three types of the transmittance curves.MnO2+3Fe2O3_??_2Fe2O3+2FeO+MnO+O2 (for high iron ratio)2MnO2+2Fe2O3_??_2Fe2O3+2MnO+O2 (for medium iron ratio)3MnO2+Fe2O3_??_Fe2O3+Mn2O3+MnO+O2 (for low iron ratio)

Theory of Coloured Glasses

Theory of Coloured Glasses

Studies on the dulabilities of coloured glasses

The author studied on the dulabilities of chrome-green and carbon-brown glasses. The results were summerised as followed:Green glasses, which were coloured by minute quantities of chrome oxide or other chrome salts, and brown glasses, which were coloured by carbon, showed the better dulabilities than those which were prepared from the batches of the same compositions except colouring materials as fomer.Tnese phenomena were considered to be caused by neither volatilisation of alkalies nor other changes of glass-compositions. Because the analysis of the above mentioned coloured and no colour glasses showed that the compositions of those glasses were regarded to be the same.