Micelle formation, thermodynamic equilibrium and compactness of chromophore-labelled styrene(hydrogenated isoprene) diblock and styrene-(hydrogenated butadiene)-styrene three-block copolymers in selective solvent systems have been investigated using nonradiative energy transfer and fluorescence quenching techniques. Donor (carbazole) or acceptor (anthracene) chromophores were randomly attached to the polystyrene part of block copolymers. The relaxation behaviour of micellar solution and the kinetics of micelle dissociation in various solvent composition and temperature were studied.