Here are a couple of definitions which I took from Epicurious.com. I hope this helps you out.
glaze-- A thin, glossy coating for both hot and cold foods. A savory glaze might be a reduced meat stock or ASPIC, whereas a sweet glaze could be anything from melted jelly to a chocolate coating. An EGG WASH brushed on pastry before baking to add color and shine is also called a glaze. glaze v. To coat food with a thin, liquid, sweet or savory mixture that will be smooth and shiny after setting.
sauce--In the most basic terms, a sauce is a thickened, flavored liquid designed to accompany food in order to enhance and bring out its flavor.