Picosecond time-resolved fluorescence spectroscopy was carried out for the aqueous solution of poly vinyl methyl ether (PVME) at two different temperatures by using a fluorescent probe molecule. The dehydration of coiled PVME, which is the initial process of coil-to-globule phase transition, was observed below the low critical solution temperature (LCST), whereas two hydrophobic environments were found inside and outside PVME. ne particles above LCST. (C) 2008 Elsevier B. V. All rights reserved.