STRUCTURE OF ZINC POLYPHOSPHATE GLASSES

The technique of high-performance liquid chromatography (HPLC) has bee n used to determine the distributions of phosphate-anion chains and ri ngs in a variety of zinc-phosphate-based glasses. The phosphate-anion distributions in simple binary zinc phosphate glasses are compared to those found in multi-cation alkali-zine phosphate glasses. Multi-catio n zinc phosphate glasses are chemically durable and can be tailored to exhibit transition temperatures sufficiently low for co-processing wi th a variety of plastics to form novel organic-inorganic composite mat erials. The intermediate range order in the multi-cation glasses is fo und to be similar to that measured in the binary zinc-phosphate glasse s. Scanning calorimetry measurements indicate, however, that the multi -cation glasses are more resistant to crystallization than the binary glasses. The fraction of phosphorus sites with 2 (Q(2)), 1 (Q(1)) and 0 (Q(0)) bridging oxygen, as well as the ratio of bridging to non-brid ging oxygen (BO/NBO), are obtained from the chromatograms. Structural data for the zinc phosphate glasses obtained using HPLC are compared t o results reported in the literature that were deduced using more-trad itional solid-state techniques such as NMR, XPS, and Raman spectroscop y. (C) 1998 Elsevier Science B.V. All rights reserved.