Stabilization of glass

Hornsby, P. R. (1980). Dimensional stability of glass-ionomer cements. Journal of Chemical Technology and Biotechnology, 30, 595-601. 

In the modern world, we are accustomed to taking the chemical stability of glass very much for granted - we rely on the durability of glass for so many things, such as windows and (until the widespread availability of plastics) bottles, as well as its use in the chemical laboratory as an extremely inert and unreactive container. In addition to its apparent inertness, glass has a number of other beneficial properties, such as its transparency or the ability to take on virtually any colour as the result of the addition of a small amount of transition metals. 

Jemlan, W. A. and Wilcox, R. C., Stability of Glass-Fiber Glass Plastics Composites, Final Report, Contract DAAH01-72-C-029, School of Engineering, Department of Mechanical Engineering, Auburn University, Auburn, Alabama, October, 1973. 

The stability of glass-forming systems is also a matter of considerable importance. Early studies have explored the association between the glassy behavior and the chemical stability (80), whereas a number of investigations have examined the recrystallization behavior of glassy drugs and excipients. In essence, the increased molecular mobility above the glass transition temperature renders recrystallization... 

The chemical stability of glass containers for pharmaceutical use is expressed by the hydrolytic resistance, i.e., the resistance to release of water-soluble mineral substances, evaluated by titrating the released alkalinity. According to the European Pharmacopoeia (2002), aqueous preparations for parenteral use are to be dispensed into glass containers of high hydrolytic resistance, while nonaqueous preparations and powders for parenteral use can be filled into glass containers of moderate hydrolytic resistance. It is obvious that release of alkaline substances may influence photochemical stability by an increase in pH (see Section 14.2.3). 

Hall, A. R., et al. Development and Radiation Stability of Glasses for Highly Radioactive Wastes, Proceedings of the Management of Radioactive Wastes from the Nuclear Fuel Cycle, vol. 2, International Atomic Energy Agency, Vienna, 1976, p. 3. 

J. A. Wise, Stability of Glass-Encapsulated Disc-Type Thermistors, in Temperature Its Measurement and Control in Science and Industry, vol. 6, pt. 1, pp. 481-484, American Institute of Physics, New York, 1992. 

Hall A. R. Development and Radiation Stability of Glasses for Highly... 

Blencke B.A., Bromer H., Deutscher K.K. 1978. Compatibility and long-term stability of glass-ceramic implants. J. Biomed. Mater. Res. 12 307-318. 

The stability of glass elements of structure relies totally on the systems that support the glass, for example the beading, seals and fixings used. 

DSC curves of glasses are shown in Fig. 1.7. It is observed that the introduction of an appropriate content of As into an As2Se3-PbSe binary system effectively enhances the thermal stability of the glass by showing a weaker or even no crystalline peak. Moreover, with an addition of PbSe an exothermal peak appears, and it becomes more intense and shifts to a lower temperature. Meanwhile, Tg increases and AT decreases the latter reveals the poorer thermal stability of glasses. In addition, Tg increases with Ge content, while it decreases as As is added, which is consistent with the previously reported work [5]. 

The hydrolic stability of glass-flber-reinforced PBT, PET and PC was studied by Kelleher et al. [42] following the changes in MFI during the process of hydrolytic degradation. Their entire approach was similar to that used earlier for reinforced PBT [43] and PC [44]. Because MFI is related to the degree of polymerization, the following relationship was developed [44] to study the rate of hydrolysis ... 

Kelleher, P. O., Wentz, R. P., Heilman, M. Y., and Gilbert, E. H., The hydrolytic stability of glass fiber reinforced poly(butylene terephthalate), poly(ethylene tere-phthalate) and polycarbonate, Pofym. Eng. Set., 23, 537-542 (1983). 

While acid corrosion in glass fibers is diffusion-controiied and therefore /f-kinetics are expected, the process in aqueous and aikaiine soiutions is considered much more complicated because of the many influencing factors. The reaction kinetics depends on the (local) pH value. It is conventional opinion that, with the switch from a diffusion-controlled corrosion mechanism to an interfacial-controlled mechanism, a rapid shift from ft-to t-kinetics takes place, and the process follows linear t-kinetics except for short exposure times and low temperatures. However, in the literature, dependencies on t are also found, with values for a varying between 0.5 and 1 [819]. The chemical stability of glass fibers under alkaline attack is also significantly influenced by insoluble corrosion or reaction products on the fiber surface. 

It may be readily recognized that, at the aimealing point viscosity of 10 Pa s (= 10 poise) and a shear modulus of roughly 10 ° Pa, the time for 90% relaxation (about 5r]IM) is of the order of a few minutes. At the strain point, where the viscosity is 10 Pa s, relaxation requires as much as 4 to 6 hours. One may also realize that the time for relaxation (or stabilization) of glass could increase to well beyond several decades at temperatures where... 

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