Borosilicate glass water

Impurity profiles of Type I borosilicate glass, water, and two different product batches... 

Fractionally distd, then 35mL was sealed with about 7g KOH pellets in a borosilicate glass ampoule and heated at 135° for 48h. The ampoule was cooled and opened, and the liquid was resealed with fresh KOH in another ampoule and heated as before. This process was continued until no further decomposition was observed. The substance was then washed with distilled water, dried (CaS04) and distd. [Grafslein Anal Chem 26 523 1954.]... 

The heating time and temperature may be considerably reduced by using aqueous sodium hydroxide in place of water. However, this reagent also involves the danger of dissolving boron from borosilicate glasses. 

Environmental water samples to be analyzed for metals are best stored in quartz or Teflon containers. However, because these containers are expensive, polypropylene containers are often used. Borosilicate glass may also be used, but soft glass should be avoided because it can leach traces of metals into the water. If silver is to be determined, the containers should be light absorbing (dark colored). Samples should be preserved by adding concentrated nitric acid so that the pH of the water is less than two. The iron in well water samples, for example, will precipitate as iron oxide upon exposure to air and would be lost to the analysis if not for this acidification. 

Advocat, T., Jollivet, P., Crovisier, J. L. del Nero, M. 2001. Long-term alteration mechanisms in water for SON68 radioactive borosilicate glass. Journal of Nuclear Materials, 298, 55-62. 

Enameling meets decorative as well as protective requirements. Ceramic enamels are mainly based on alkali borosilicate glasses. The part to be enameled is dipped into or sprayed with a slip, ie, a water suspension of glass fragments called frit. The slip coating is dried and fused in an enameling furnace under careful heat control (see Enamels, porcelain or vitreous). 

Thermal Expansion. Most manufacturers literature (87,119,136—138) quotes a linear expansion coefficient within the 0—300°C range of 5.4 x 10"7 to 5.6 x 10 7 /°C. The effect of thermal history on low temperature expansion of Homosil (Heraeus Schott Quarzschmelze GmbH) and Osram s vitreous silicas is shown in Figure 4. The 1000, 1300, and 1720°C curves are for samples that were held at these temperatures until equilibrium density was achieved and then quenched in water. The effect of temperature on linear expansion of vitreous silica is compared with that of typical soda—lime and borosilicate glasses in Figure 5. The low thermal expansion of vitreous silica is the main reason that it has a high thermal shock resistance compared to other glasses. 

Densities required for the calculation of viscosity were obtained in three ways. The densities of the salt solutions were measured by Archimedean displacement (9) of a borosilicate glass bob weighed in air, water, and the solvents and solutions. The results were expressed as linear functions of the molar concentration of salt, and the slopes obtained are recorded in Table II. Densities of the solvent mixtures were taken from published tables (10,11). Densities of the stock acetone and methanol were measured by a conventional pycnometer to greater precision than the salt solutions, and they were compared with the literature values for analysis and with the values obtained by displacement as a check. The two methods agreed within 0.0005 g/ml. 

Figure 9.5—A 5 MHz NMR spectrum of a water sample in a borosilicate glass container (magnetic field in gauss Varian document). There are no commercial instruments of this type because NMR is not sensitive enough to solve many of the problems encountered in elemental analysis.

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