Hydrous glasses

Behrens, H. and Stuke, A. (2003). Quantification of H20 contents in silicate glasses using IR spectroscopy - a calibration based on hydrous glasses analysed by Karl-Fischer titration. Glass Science and Technology 76 176-189. 

Figure 6.29. MAS projection of the Si-O-Si peak in the O MQMAS NMR spectrum of dry and hydrous sanidine (KAlSisOg) glass. Note the lack of additional intensity in the spectrum of the hydrous glass (denoted by the broken line) indicating the absence of significant silanol concentration. From Oglesby et al. (2001) by permission of the Mineralogical Society of America.

NMR of hydrous glasses. The effect of water in silicate and aluminosilicate... 

Glasses prepared by sol-gel methods may be regarded as examples of hydrous glasses since they can retain significant proton levels when the gel is dried and vitrified. 

H. Behrens and A. Stuke, "Quantification of H20 contents in silicate glasses using ER spectroscopy a calibration based on hydrous glasses analyzed by Kail-Fischer titration," Glass science and technology, vol. 76, no. 4, pp. 176-189,2003. 

Reactions with analcite to form hydrous glass ... 

It is clear (1) that there are differences in the natures of allophanes from different volcanic ash soils (2) that these differences grade with maturity of the soils and (3) that in very mature well-drained volcanic ash soils allophane grades into metahalloysite. Some of the nature of the different phases of allophane represents a complicated sector of soil-colloid science that requires further elucidation. In the meantime, pending satisfactory characterization of allophanic constituents such as hydrous feldspars, hydrous glasses, limited gels, extended gels, and halloysite intermediates, the concept... 

Note Tirau and Egmont clays are predominantly allophane. Hydrous glass and feldspar are in higher proportions in clays of Taupo and Mahia soils. 

Miyauachi and Aomine [1964] questioned the evidence for the existence of allophane B and that the presence or absence of a high-temperature exothermic peak is related to particle size. This was discussed in Section D.II., which concludes that many particles less than 0.2 jtim in size are allophane A and that the particles between 2 and 0.2 ftm may be other forms of allophane, such as hydrous glasses or feldspars. 

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