(working life) n. (1) The period after mixing the ingredients of an active compound during which the viscosity remains low enough to permit normal processing. Dissatisfied with the vagueness of this definition, Breitigam and Ulrich (August, 19990) cautiously defend pot life or their epoxy compounds as the time, at room temperature, for the viscosity to reach double its initial value. (2) The length of time a paint material is useful after its original package is opened, or after catalyst or other ingredients are added. Also called usable life, spreadable life. See working time.