This paper describes the method for the determination of Ba in television tube glass by atomic absorption spectrometry.
As the absorbance of Ba is increased by the addition of K, it is decided that 4000ppm K is added in this experiment.
The interference of the glass components to the Ba determination is as follows;
(i) Sr, Ca, Mg, Sb, As and Fe do not interfere.
(ii) Al, Ti, Zr and Si decrease the absorbance of Ba.
In case that 60ppm Ba and 4000ppm K are in the solution, 100ppm Al, 6ppm Ti, 60ppm Zr and 0.5ppm Si are allowable.
The method of determination is as follows;
0.5g of powdered glass sample is decomposed by HF and HClO₄, and Si is completely eliminated as SiF₄. The residue is dissolved by dilute HCI. The contents of Al, Ti and Zr are within the limit, an aliquot of the sample solution and potassium nitrate solution are transferred to the volumetric flask so that the final concentration of analyte will be 10 to 60ppm Ba and 4000ppm K. Then Ba is determined by atomic absorption spectrometry.
In case that the contents of Al, Ti and Zr are over the limit, it is necessary to remove them by the hydroxide precipitation method. And then Ba is determined as mentioned above.
The average relative difference is about ±5% and reasonably good results are obtained in the range of about 2 to 6 per cent barium oxide in the television tube glass.

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It has been known that Mg²⁺ has a marked tendency to form the lustrous flake (spicule) in the water stored in glass containers. In order to elucidate the role of Mg²⁺ in the flake-formation, the reaction in the Mg²⁺-SiO₂-H₂O system in a glass container has been studied.
Slightly alkaline aqueous solutions, with or without SiO₂, which contained Mg²⁺ less than 16ppm and adjusted to pH range from 7.5 to 9.4, were heated in a silica glass flask at temperatures below 90°C, within 72h. The measurment of changes of the Mg²⁺- and SiO₂-concentration and the observation of the flake-formation were carried out. The reaction products formed in the state of film on the glass surface were identified as magnesium silicate hydrates, which were similar in composition to sepiolite but had very low crystallinity, by means of chemical analysis, X-ray diffraction, DTA and IR absorption spectra.
The Mg²⁺ concentration decreased with heating time, and approached finally to almost zero in the solution at pH 9.0 as most of the Mg²⁺ were consumed for formation of the film on glass surface. The SiO₂ concentration increased in contrast to the Mg²⁺ concentration by dissolving of silica from the glass surface. The concentrations of Mg²⁺ and SiO₂ depended on both the pH value and temperature of the solution. No flake-formation was observed at pH below 8.0.
The role of Mg²⁺ in the flake-formation might be considered as follows;
1) The hydrated silica layer formed in gel-state on glass surface by the action of OH^-, is tightened due to the formation of magnesium silicate hydrate film and therefore the durability of the gel-layer to water increases.
2) OH^- and Mg²⁺ remaining in the water can enter into inner side of the film through small openings of the film, and the thickness of the film increases successively.
3) The break-down of the film is directly or indirectly caused by its own contractile force as a whole, with increasing of the thickness.

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The investigation on the relation between the heat of solution of alkali borate glasses and crystals in the system R₂O-B₂O₃ (R=Li, Na, K) and the co-ordination change of boron with composition was carried out.
The results are summarized as follows;
1) The heat of solution per mole B₂O₃ was expressed as a function of molar ratio R₂O/B₂O₃. The composition depedences for the glasses were shown by curves with concave curvature and that for crystals were well represented by segments of straight lines, in which the break points were observed, one in each system of Li₂O-B₂O₃ and Na₂O-B₂O₃ and two in K₂O-B₂O₃ system. The break point compositions correspond to those of the congruent melting compounds Li₂O⋅2B₂O₃, Na₂O⋅4B₂O₃, K₂O⋅4B₂O₃ and K₂O⋅2B₂O₃.
The calculated heat of crystallization from the above results showed the maximum at the composition of the congruent melting compound in each system.
It is possible to conclude from the results obtained above and the similar ones observed in alkali germanates in our previous papers that these energy relations are characterisic of glassforming systems with the dual co-ordination behaviors of the networkforming ion.
2) It was observed in comparison with these results and the well known results of NMR studies by Bray et al. that the heat of crystallization in these systems was closely related to the energy change caused by the difference between the composition dependences of boron co-ordination change in glasses and that in crystals. From the above facts, the authors derived the empirical rule on the correlation between the heat of crystallization and the coordination change of boron.

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The hollow glass micro-sphere named “Shirasu-balloons” can be produced from the Shirasu, which is a kind of acidic volcanic ejecta. Shirasu-balloons has fewer partition bubbles and shows different surface state, compared with the “perlite” which can be produced from obsidian and perlite, which are the other kinds of volcanic glasses. These differences mean that foaming mechanism of Shirasu-balloons is not similar to that of the other volcanic glasses. And a few points of difference between volcanic glass grains in the Shirasu and grains of the other volcanic glasses on heating stage were found.
(1) Some small groove-like cracks were observed on the surface of Shirasu-balloons. These grooves come from the difference of softening temperature between the surface layer in which Na⁺ was exchanged by H⁺ during weathering time and the inside part in the Shirasu natural particles.
(2) The difference of softening temperature between the surface layer and the inside part seems to keep the shape of the Shirasu-balloons spheric and prevent to stick each other during heating treatment, and more over seems to be effective to make particle expand in the direction to inside of the grain and to extinct partitions wall of cell in the Shirasu-balloons.
(3) The number of bubbles formed in a grain seems to be in proportion to number of crystallites in the volcanic glass, and these crystallites dissolved when the volcanic glass expand at heat treatment. These results disclosed that these crystallites in the volcanic glass act as foaming cores during heating treatment.

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This study was concerned with the formation and color development of the spinet solid solution in CoO-ZnO-Al₂O₃-Cr₂O₃-SnO₂ system, and its application to colored glazes.
Specimens were prepared by calcining the oxide and hydroxide mixture at 1450°C for 1h. The formation of spinel solid solution was examined by X-ray diffraction, the color was discussed by measuring the spectral reflectance, and the stability of the spinel in glazes was tested.
The results were summarized as follows.
1) Except a few systems, formation of a continuous solid solution was confirmed by X-ray analysis.
2) As the amount of Cr³⁺ increased in ZnO-Cr₂O₃-SnO₂ system, the color changed from white through grayish olive green to beige, and the absorption of Cr³⁺ shifted towards violet region.
3) An increase of Cr³⁺ in ZnO-Al₂O₃-Cr₂O₃ system, caused the color to change from white through purplish pink to beige, and the absorption of Cr³⁺ shifted towards red region.
4) The color obtained in ZnO-Al₂O₃-Cr₂O₃-SnO₂ system in the region in which single spinel formed, ranged from white through grayish olive to grayish brown.
5) An increase of Cr³⁺ in Coo-ZnO-Cr₂O₃-SnO₂ system, yielded colors ranging from grayish olive through grayish olive green to strong blue green, and the absorption of Cr³⁺ shifted towards violet region.
6) As the amount of Cr³⁺ increased in Coo-ZnO-Al₂O₃-Cr₂O₃ system, colors ranging from vivid blue through strong greenish blue to strong blue green developed, and the absorption of Co²⁺ and Cr³⁺ shifted towards red region.
7) As the amount of Al³⁺ incresed in Coo-ZnO-Al₂O₃-SnO₂ system, the color changed from grayish olive through grayish sky to vivid blue, and the absorption of Co²⁺ shifted towards violet region.
8) Colors ranging from light greenish gray to strong blue green developed in CoO-ZnO-Al₂O₃-Cr₂O₃-SnO₂ system in the region where single spinel formed.
9) According to the results of the colored glaze test, formation of a new spinel was observed in the case of magnesia-calcia glaze, and the specimens with the composition of Cr³⁺ rich region were stable as a glaze stain.

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炭酸バリウムと酸化チタンからメタチタン酸バリウムを合成する反応に対する弗化リチウムの反応促進作用を研究した. 弗化リチウムを添加すると炭酸バリウムの分解反応およびメタチタン酸バジウムの生成反応が促進されるのが認められた. 炭酸バリウム, 酸化チタンおよび弗化リチウムの三成分が共存する場合の炭酸バリウムの分解反応はこれら三成分が同時に相互作用することが必要であることを示した. この三成分の同時相互作用の際, リチウムイオンはバリウムイオンより強く炭酸塩に作用し, 酸化チタンとの反応により分解するのを促進していることを認めた. また弗素イオンはこの分解反応を促進する効果があることがわかった. 三成分の同時相互作用により生成した分解反応の中間生成物であるチタン酸リチウムと弗化バリウムはさらに反応してメタチタン酸バリウムを生成することを示した. 弗化リチウムの作用下でのメタチタン酸バリウムの生成は, このメタチタン酸リチウムと弗化バリウムの反応および弗化バリウムの弗素の作用下での炭酸バリウムと酸化チタンの直接反応の同時進行によるとして説明できる.

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Sb-doped BaTiO₃ powder was readily synthesized by the addition of a dilute isopropyl alcoholic solution of tetraisopropyl titanate to an aqueous solution of barium hydroxide containing antimony ion. Under the optimum conditions the powders having the ratio (BaO/TiO₂)=1.05 were prepared, being analyzed by a wet chemical method.
The average grain size of the powders was estimated to be about 200 Å from the half height width of an X-ray diffraction peak. Sintered bodies from the powders exhibited the semiconducting property similar to that of a usual semiconducting barium titanate prepared by a solid state reaction. The amount of antimony in the powders was determined by polarography.

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Darkening characteristics of silver chloride photochromic glass based on Li₂O-Na₂O-B₂O₃-Al₂O₃-SiO₂ system was markedly improved by reheating at temperatures even below melting point of silver chloride. Structural change of silver chloride particle precipitated in the glass with reheating was investigated by X-ray diffraction method. (111), (200), (220) and (222) lines were used for structural analysis. The lattice spacing of AgCl particle was increased and ratio of diffracted intensity I₍₁₁₁₎/I₍₂₀₀₎ was decreased with the increase of reheating temperature. These facts showed that the ‘AgCl’ particles in glass is a solid solution of AgCl and NaCl and the reheating changes the state of solid solution within the particle. The lattice strain in ‘AgCl’ particle estimated from half-height width of (111) and (222) lines showed maximum around 400°C, being related to the photochromic characteristics.

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