W0217

A NMR Study of the Ge-P-S Glass System. B. Cherry^*, J. McLaughlin^*, B. Aitken^**, and J.W. Zwanziger^*, ^*Department of Chemistry, Indiana University, Bloomington, Indiana 47405, ^**SP-FR-05, Corning, Inc., Corning, New York 14831

To understand the excellent optical and mechanical properties, an investigation of the phosphorus environments in the Ge-P-S glass system was carried out through the use of solid-state NMR in combination with other techniques. In the P-S system, glasses have been shown to contain vestiges of molecular clusters¹. All phosphorus in the system are in formally positive oxidation states, which produces electron poor species. In the Ge-P system, phosphorus is present as phosphides, leading to electron rich species. Thus the Ge-P-S system can be tuned from electron poor phosphorus sulfides to electron rich phosphides.

The glass samples used in this study were of composition Ge_2.5-P_1.0-S_x, x= 5.0 to 8.0. Magic Angle Spinning NMR experiments reveal the types of phosphorus environments. Experiments such as RFDR² and phosphorus double quantum³ give information about spatial proximity and connectivities of the phosphorus in the glasses. For a complete structural determination of a multicomponet system, solid-state NMR must be complemented with other techniques such as neutron diffraction and wide-angle X-ray diffraction. Combining all data, real space models of multicomponet glass systems can be generated.

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