SHORT AND INTERMEDIATE RANGE ORDER IN GLASS - NUCLEAR-MAGNETIC-RESONANCE PROBES OF SITE CONNECTIVITIES AND DISTANCES

We present results on the spatial distribution and connectivity of pho sphate in silver iodide-silver phosphate glasses, as a function of sil ver iodide and silver oxide content. These results were obtained using several different nuclear magnetic resonance experiments which give s elective signals for phosphorous atoms which are in spatial proximity to one another. Our data show that the silver iodide in these glasses acts to spread the phosphate chains apart, and that, in highly modifie d phosphates, a distribution of chain lengths exists, with chain lengt hs as short as two phosphate units. (C) 1997 Elsevier Science B.V.