Anhydrous sodium ultraphosphate glasses were prepared with Na 2O contents between 0 and 50 mol% and were characterized by several structurally sensitive spectroscopic probes to determine the nature of the phosphate tetrahedra that constitute the short-range glass structure. Solid state 31P magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy reveals that Na 2O depolymerizes the branched (Q 3) P-O network of P 2O 5 to form metaphosphate (Q 2) sites, in quantitative agreement with Van Wazer's “chemically simple” model. X-ray photoelectron spectroscopy reveals that the concomitant increase in non-bridging oxygen with increasing Na 2O content is also in quantitative agreement with this structural model. Raman spectroscopic analyses of glasses with approximately 40 mol% Na 2O suggest that some intermediate-range order, perhaps associated with strained rings, also exists within the glass network. Strained sites are eliminated when the solid glass is heated to melt temperatures. © 1994.