Recent work has demonstrated the production of substantial molecular alignment in a free ethylene glycol jet. Using variably polarized photoselection, a range of initial nonequilibrium orientational distributions can be prepared and their subsequent relaxation monitored via polarization resolved time correlated single photon counting. The imposition of order in a fluid is seen to have a profound effect on molecular motion and a strong anisotropy in theta and phi diffusion is indicated. In this work (Papers I and II) we describe a detailed investigation of this phenomenon. Here (Paper I) we develop the formalism necessary to describe the interaction of polarized laser pulses with an anisotropic medium, allowing a full description of the initially photoselected distribution. The relaxation of the nonequilibrium distributions is considered via a perturbation treatment of the anisotropic rotational diffusion equation. New "selection rules" for orientational relaxation can be deduced from symmetry arguments and the form of the cylindrically symmetric (theta diffusion) and asymmetric alignment decays (phi diffusion) are predicted.