Silicate borosilicate glasses

Risen and Wang developed a method and compositions for producing microlenses and optical filters. According to their method, carboxylated silicone or polysilicone precursor composition is applied to the surface of a substrate to form a precursor droplet, which is thermally oxidized to form a microlens. The substrates utilized were silica, silicates, borosilicate glasses, and silicones. The precursors, which are present in concentrated solutions, are viscous fluids which are used to form microdroplet precursors. A solvent such as ethanol or acetone is added to the precursors to modify and control their flow and surface tension properties, to facihtate the formation of spherical shape of the precursor on substrates. The precursor droplet volume is 4-600 picoliters and forms a droplet of 20 to 1000 micrometers in diameter. 

A convenient method to introduce organic functions into inorganic networks is the use of substituted siliceous acid esters and the sol-gel route. The basic reactions, therefore, are given in Equations 1 and 2. Equation 1 describes the sol-gel reaction to a borosilicate glass. 

In the broad use of the word polymer, ion-containing polymers are ubiquitous. They include inorganic substances such as silicate and borosilicate glasses discussed in Chapter 4, most biopolymers, solvent-swollen synthetic ion exchangers and some synthetic structural polymers. With few exceptions, these exhibit the characteristic feature of an electrolyte, ion mobility. In this chapter we consider the group of synthetic... 

The nature of the reactants can be varied giving various silicate-like products. Equation 12.17 describes the formation of borosilicate glasses using the sol-gel approach. 

Zhao, D., Li, L., Davis, L. L., Weber, W. J. Ewing, R. C. 2001. Gadolinium borosilicate glass-bonded Gd-silicate apatite A glass-ceramic nuclear waste form for actinides. Materials Research Society Symposium Proceedings, 663, 199-206. 

Del Nero, M., Advocat, T., Jollivet, P. Bontems, G. 1999b. Sorption of neptunium (V) on an alteration gel of alumino-borosilicate glasses and on synthetic silicate gels. Proceedings 2nd International Symposium on Nuclear Fuel Cycle Safety Engineering Research Facility NUCEF 98, Hitachinaka, Ibaraki, Japan, 584-595. 

Chemical Properties. The chemical durability is a function of the durability of the crystals and the residual glass. Generally, highly siliceous glass-ceramics with low alkali residual glasses, such as glass-ceramics based on quartz and (3-spodumene, have excellent chemical durability and corrosion resistance similar to that obtained in borosilicate glasses. 

Boronic esters of (R,R)-l,2-dicyclohexyl-l,2-ethanediol or pinanediol react with thionyl chloride and excess imidazole in acetonitrile on a borosilicate glass surface to form the corresponding cyclic sulfites of diols <20010M2920>. Similarly, cyclic sulfites and sulfates have been prepared from silicates of diols <1997TL4841>. 

Chromatographic System (See Chromatography, Appendix IIA.) Use a gas chromatograph equipped with a flame-ionization detector and containing a 2.4-m x 4-mm borosilicate glass column, or equivalent, packed with 2% liquid phase 5% phenyl methyl silicone (SE 52, or equivalent) on an 80- to 100-mesh siliceous earth support (Diatoport S, or equivalent). Maintain the column isothermally at a temperature between 270° and 280°, and the injection port and detector block at about 310°. Use helium as the carrier gas at a flow rate of about 70 mL/min. 

The refractive index values of solid oxides lie in the range of 1.3 to 2.7 with silicate glasses they vary between 1.5 and 1.9, while extreme values exhibited by special glasses are 1.35 and 2.25. The Abbe value lies in the range of 20 to 100. Current soda-Iime--silica and borosilicate glasses have 1.48 — 1.53 and v = 58 —70. The refractive index is increased most by PbO and BaO. The dispersion usually increases simultaneously with refractive index. 

The above considerations of the chemical durability and corrosion of glass were concerned with current types of silicate and borosilicate glasses. Special types of glass may exhibit quite different behaviour and also require special test methods. 

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