This paper describes the dynamics of new slow release formulations of plant growth regulator (PGR) 1-naphthylacetic acid (NAA) in aqueous solution. The new PGR formulations are water-soluble copolymers derived from acrylamide and vinyl chloroethyl ether, containing side linkages of NAA the latter being released after hydrolysis. From the observed photon correlation spectra of the polarized scattered light of the water-soluble PGRs, the distribution of relaxation times is computed by means of a direct Laplace transformation The results of the light scattering experiments suggest that the incorporation of the hydrophobic naphthyl group dramatically affects the conformation of the parent polymer. The interactions between the hydrophobic NAA groups lead to the formation of interpolymeric micellar structures. The hydrodynamic radius R-h which is 42 Angstrom for the parent polymer (PF1), increases to 70 Angstrom for the NAA polymeric ester with 1.94% mol content (PF2) and becomes 82 Angstrom by increasing the amount of the hydrophobic substituent to 3.54 mol.% content (PF3). The scattering intensities and apparent hydrodynamic radii display a systematic drop as a function of time due to the loss of the NAA linkages and R-h becomes 58 Angstrom for PF2 and 68 Angstrom for PF3, 116 h after the preparation of the water polymeric solutions.