An evaluation of the light-protective and industrial properties of colored container glasses

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The data on the ionic staining of glasses are analyzed from the standpoint of ligand field theory. New information is added to the existing information on the staining of glasses by transition-metal compounds. Data on the structure of glass-forming melts and the conditions for the formation of staining complexes are presented. A possible mechanism for amber staining in glasses is discussed.Ionic staining of glasses is accomplished, as a rule, with transition and rare-earth elements. Some of these compounds can also be used for decolorize glasses, which is a kind of staining.The current view is that staining is due to the formation of coordination (complex) compounds in which the character of the chemical bond is studied from the standpoint of the valence-bond, crystal-field, and molecular-orbital theories [1 -3]. The basic tenets of these theories as applied to the transition elements are gathered under the name "ligand field theory." The methods used in this theory make it possible to calculate quite accurately the spectral characteristics of coloring complexes, including for glasses [1, 3 -5].The present article presents a complete analysis of ionic staining of glasses. The relationship between color centers and the basic structural elements of glasses is very important for glass technology. This relationship is quite complicated and can be viewed, for example, from the standpoint of the solvation interaction, whose basic ideas as applied to solutions are developed in the monograph [6] and have essentially not been studied for glasses.Ligand field theory studies the interaction of ligands on the d or f orbitals of a complexing ion. Ligands split the corresponding energy levels of the orbitals.The present article will focus on ionic staining determined by the 3d orbitals of ions of transition elements and oxygen ligands. In addition, the mechanism proposed for the formation of complexes with mixed ligands will be examined for the example of amber staining of glass.Ionic staining of glass by transition-metal compounds, as a rule, is associated with octahedral and tetrahedral arrangements of ligands around a complexing ion. The form and spatial arrangement of the d orbitals and their energy levels in the octahedral and tetrahedral environment of ligands (for one spatial variant) are displayed in Fig. 1. In an octahedral ligand field three electron orbitals occupy the lowest energy level d e while two orbitals occupy the higher energy level d g . The opposite picture is observed in a tetrahedral ligand field. When studying transition elements with an increasing numFree ion z z y y x x d g d g d e d e D D à b Fig. 1. Splitting of the energy levels of d electrons in octahedral (a) and tetrahedral (b ) fields of oxygen ligands.

Section: It Follows From These Schemes That [Cro 4 ] 2-is An Innerorbmentioning

confidence: 99%

Complete analysis of ionic staining of glasses by transition-metal compounds

Guloyan

2007

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“…Aside from the transformation of the spectral curves as the Fe 2+ concentration increases, the index of the diathermancy (ID) of the melt, calculated according to the expression [2,3] ID = 10 -1 t 1100 ,…”

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confidence: 99%

Heat tolerance of green glass containers

Atkarskaya

Raspopov²,

Chartii

et al. 2011

The effect of individual production factors on the heat tolerance of glass containers is studied. It is shown that the use of quartz raw material distinguished by its fineness from the material adopted for a technological process in a given glass-making furnace can result in massive production rejects, consisting in the appearance of seeds and heat intolerance. The phenomenon is explained from the standpoint of oscillations of the heat tolerance index of molten glass.

“…On the basis of the data presented above, the results of spectral photometric measurements of radiation transmission in the range 300 -500 nm can be used to assess the protective properties of colored container glass [24]. The long wavelength part of the spectrophotometric curve (1000 -1100 nm) must be taken into account when evaluating the diathermancy of glass.…”

mentioning

confidence: 99%

Serviceability of glass and glassware (review)

Guloyan

2008

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Research on the properties and characteristics of glass that determine the serviceability of the most massive glass objects and glassware is reviewed. The theoretical assumptions, general questions concerning the strength, chemical resistance (corrosion), and spectral characteristics of glass are noted. The properties and characteristics indicated are examined for sheet glass, glass fiber, and glassware.The serviceability of glassware is characterized by a predominant indicator or group of indicators. For mass-produced articles (sheet glass, glass containers) high serviceability is achieved primarily by adequate strength, chemical stability, and the required spectral characteristic. All sheet glasses and glass containers must have adequate strength and chemical stability, while only certain types of articles require definite spectral characteristics (heat protective, heat reflecting, and other articles made of sheet glass; glass containers for medicines, wines, beer, juices, and certain other types of medical and food products; some types of glass containers must also have adequate heat resistance).In the last few years the production of glass fibers has grown intensively as a result of the expansion of applications for articles based on them. Glass fibers are most widely used in composite materials where which strength is decisive. Despite high performance in other spheres of application (electric insulation, light guides, and so forth), strength remains a very important property of glass fibers.Analysis of data obtained over a long period of time using the SkiGlass system [1] shows that investigations of operating properties and characteristics such as the CLTE, optical properties, and chemical stability, comprise a substantial fraction of all investigations performed. At the same time the number of investigations concerning strength, which is an important property, is clearly inadequate (about 1% over the period 1976 -2001). Apparently, this is because the basic results of previous investigations and commercial developments are widely known. The existing methods for increasing substantially the strength of massive glass, specifically, sheet glass, are quite time-consuming and only of limited use. In this connection, large users of commercial glass, for example, in construction, prefer using low-strength but much cheaper glass and articles based on it.The serviceability of glassware is directly related with the structure, state, and volume and surface properties of glass.General questions concerning and the serviceability of sheet glass, glass fiber, and glass containers, which comprise about 90% of everything produced by the glass industry, will be examined below.This review is based mainly on published review articles containing a substantial number of citations to original works GENERAL STRUCTURAL CHARACTERISTICS OF GLASSInorganic glass, including silicate glass, exhibits characteristic structural features on different microscales [2 -4].In regions which have essentially atomic dimensions (region of short-ra...