ISSN:
1573-4803
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Raman spectra have been measured on bulk GeO2 glass and the alkali germanate glasses of composition M2OxGeO2 where M=K, Na, Li, and x varies from 19 to 1, as well as on crystallized glasses. The low alkali content glasses (x≥3) retain a completely polymerized structure of germania polyhedra. Addition of small amounts of alkali oxide to GeO2 glass does not break the Ge-O-Ge bridging bonds and creates higher co-ordination of germanium atoms. Further addition of alkali oxide eventually breaks up some of the Ge-O-Ge bonds to create Ge-O− non-bridging oxygens. In the K- and Na-glasses a small number of non-bridging oxygens already exist at x=4.5, while in the Li-glasses they do not exist even at x=4. The structures of the low alkali content glasses start to disappear at x between 4 and 3 and they disappear almost completely at x=2. At x between 2 and 1, glass structures become analogous to the silicate glass structures. At x=2, the glass consists of disordered (Ge2O5) n sheet-like structures and at x=1 disordered (GeO3) n chain structures.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00550581
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