We present exact quantum calculations of the photodissociation of ozone in the Hartley band. These calculations rely on an hyperspherical description of the system, including rotation. A pseudospectral approach has been used for an efficient implementation of this scheme. The autocorrelation function has been directly computed by means of a Lanczos scheme, augmented by a complex absorbing potential. Using a single excited potential energy surface (D B-1(2)), calculations up to J=17 are reported. It is shown that in these conditions rotation has only marginal effects over the first 500 fs. The origin of the observed experimental temperature dependence is discussed in this context. (C) 2001 American Institute of Physics.