An aqueous binder composition, useful for making fiber products, especially fiberglass insulation, comprising an aqueous substantially alkaline (pH of at least 5.0) solution of a polyol and a hydrolyzed (solubilized) copolymer of maleic anhydride and a vinyl aromatic compound, preferably styrene (i.e., a SMA copolymer); the copolymer is solubilized using ammonia, an ammine, a primary alkanolamines (preferably monoethanolamine), a secondary alkanolamine (preferably diethanolamine (DEA)), a tertiary alkanolamine (preferably triethanolamine (TEA)), or a mixture thereof and the binder composition is cured as a consequence of cross-linking, esterification reactions between pendant carboxyls on the solubilized (hydrolyzed) copolymer (SMA) chains and hydroxyl groups of the polyol, including the diethanolamine and/or triethanolamine preferably used in the solubilization of the SMA.