%0 Journal Article %A Kamitsos, E.I.%A %A Varsamis, C. P. E.%A %A Vegiri, A. %D 2020 %T Spectroscopic studies of mobile cations in glass %J Physics and Chemistry of Glasses: European Journal of Glass Science and Technology Part B %V 60 %@ 17533562 %R 10.13036/17533562.61.3.Kamitsos %I Society of Glass Technology %P 107–122 %N 3 %U https://hdl.handle.net/10442/18019 %X The nature of metal ion sites in alkali and alkaline earth borate glasses and in sodium silicate and aluminosilicate glasses has been discussed on the basis of far infrared spectroscopic results. It was proposed that regardless of differences in short range order of glasses and nature of metal ion, the far infrared results can be understood in a unified way which is based on the presence of at least two types of site, i.e.singly and doubly occupied metal ion sites. The study of Li borate glasses by molecular dynamics simulations helped to elucidate the nature of the local borate units constituting the two types of site and to correlate the type of sites with the Li ion site vibrational response in the far infrared. The distinction between different types of site in silicate glasses can be based on the number of nonbridging oxygen atoms involved in the metal ion coordination sphere. It was discussed that the “two site” model for binary glasses incorporates elements of the continuous random network model of Warren–Biscoe and Zachariasen and of the modified random network model of Greaves. Experimental results from dielectric spectroscopy, probe ion spectroscopy and multiple-quantum magic-angle spinning NMR on alkali borate and silicate glasses were discussed in terms of the “two site” model. %> Αποθετήριο Ήλιος / ΕΙΕ