Multiple molecular relaxations of hot‐drawn and quenched polymers above their glass transition temperatures

Abstract Thermal shrinkage of highly hot‐drawn and quenched poly(methyl methacrylate) and polycarbonate of bisphenol A were measured. PMMA shows three‐step thermal shrinkage under suitable experimental conditions above its glass transition temperature ( T g ). Polycarbonate exhibits four kinds of molecular relaxation associated with shrinkage around and above its T g . The effect of hot‐drawing and quenching conditions on shrinking behavior is discussed. Almost all of the molecular relaxations are observed above T g . The molecular origins of the relaxations are discussed in relation with the so‐called T 11 transitions of polymers.