Dynamic Light Scattering in Network-Forming Glasses David Sidebottom, Physics Department, Creighton University, Omaha NE 68178 How does the underlying covalent structure of oxide glasses influence the dynamics of the melt? Adding alkali to phosphorus pentoxide converts the 3D network to 2D chains (crosslinked by the alkali ions). Dynamic light scattering in the liquid characterizes the fragility of the glassformer. Our studies of Na2O-modified P2O5, inidcate changes in the liquid fragility which are identical to those seen in chalcogenide glasses as a function of the mean bond density, <r>, suggesting a common origin in the destruction of the oxide network in both systems. P2O5 NaPO3 network polymer chains + Na