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'Phosphate Glasses' in keywords Facet   Publication Year 1995  [X]
Facet   section ZfN Section A  [X]
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1995[X]
1Author    M. Born, C. Feike, H. W. Jäger, SpiessRequires cookie*
 Title     
 Abstract    Dedicated to Prof. W . Müller-Warmuth on the occassion of his 65th birthday Recently, 31P two-dimensional (2D) NMR has been proposed as a powerful tool for direct investigations of the connectivities between the Q" units in glasses, i.e. the medium-range order. In this paper, the principles of these experiments and applications to both polycrystalline Mg2P20 7 and a Na20 -P 2C>5 glass are demonstrated, including a theoretical description and modelling of the polarization transfer between the two inequivalent phosphorus sites in the magnesium pyrophos­ phate. 2 D 31P E x c h a n g e N M R : A new A p p r o a c h f o r a D ir e c t P r o b in g o f th e C o n n e c tiv itie s o f Q 1 U n its in G la s s e s 
  Reference    Z. Naturforsch. 50a, 169—176 (1995); received September 26 1994 
  Published    1995 
  Keywords    Exchange NMR, Connectivities, Phosphate glasses, Dipolar coupling, MAS 
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 TEI-XML for    default:Reihe_A/50/ZNA-1995-50a-0169.pdf 
 Identifier    ZNA-1995-50a-0169 
 Volume    50 
2Author    Uwe Hoppe3, Günter Walter8, Dörte Stachelb, AlexC. HannoncRequires cookie*
 Title     
 Abstract    h o r t-R a n g e O r d e r D e ta ils o f M e ta p h o s p h a te G la s s e s S tu d ie d b y P u ls e d N e u tr o n S c a tte r in g Details of the short-range order of the binary metaphosphate glasses A1P30 9 and PbP2Oe and the ternary glass system ZnO-MgO-2P2Os have been studied by pulsed neutron scattering which provides a measuring range up to about ß m ax = 500 nm-1. The splitting of the P-O peak in the distance correlation functions attributable to the different bond lengths for the non-bridging and bridging oxygens was found to decrease with increasing field strength of the network-modifier cations. For the ternary system ZnO-MgO-2P2Os the peak in the distance correlation function, T(r), produced by the first oxygen neighbours around Zn2+ and Mg2+ was separated by the additional use of the X-ray structure factor. The distances rZn0 and rM gQ extracted from the separated peaks are slightly different from those obtained from the binary glasses ZnP20 6 and MgP20 6. The metal-oxygen coordination numbers were found to be NZn0=4.5 and NM g0 = 5.5. For the two binary systems the coordination numbers Al-0 and Pb-0 were obtained to be 7 and 5, respectively. 
  Reference    Z. Naturforsch. 50a, 684—692 (1995); received March 6 1995 
  Published    1995 
  Keywords    Pulsed neutron scattering, phosphate glasses, short-range order 
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 TEI-XML for    default:Reihe_A/50/ZNA-1995-50a-0684.pdf 
 Identifier    ZNA-1995-50a-0684 
 Volume    50