In this paper we report the derivation and the performance of a spin-restricted density functional formalism for linear time-dependent properties in open-shell molecules. The formalism is based on an exponential parameterization of the density operator with the response functions defined through Ehrenfest's principle. In addition to the derivation of formulas, details of implementation are given as well as a discussion of numerical results for excitation energies and dynamic polarizabilities for a selected set of radicals. (C) 2003 American Institute of Physics.