Synchrotron small-angle X-ray scattering was used to investigate the ordering of quenched poly(ethylene oxide) (PEO) samples when they were heated up from room temperature to the melting point. At the temperature below 50℃

a local ordering involves the change of chain conformation in the lamellae and crystallization in the vicinity of lamellae of the areas between lamellae; while upon 50℃

a cooperative ordering occurs which includes PEO chains in disorder state crystallizing

larnellae thickening and coupling of them. While the samples were heated up to 58℃

the thin lamellae melt and then recrystallize into thick lamellae

giving rise to an increase of crystallinity.