Dissociative direct photoionization of the N2O(X (1)Sigma(+)) linear molecule via the N-2(O)+(B (2)Pi) ionic state induced by linearly polarized synchrotron radiation P in the 18-22 eV photon energy range is investigated using the (VA+ V-e,P) vector correlation method, where VA+ is the nascent velocity vector of the NO+, N-2(+), or O+ ionic fragment and V-e that of the photoelectron. The DPI processes are identified by the ion-electron kinetic energy correlation, and the Ichi(A+) (theta(e),phi(e)) molecular frame photoelectron angular distributions (MFPADs) are reported for the dominant reaction leading to NO+(X (1)Sigma(+),v) + N(D-2) + e. The measured MFPADs are found in satisfactory agreement with the reported multichannel Schwinger configuration interaction calculations, when bending of the N2O+ (B (2)Pi) molecular ion prior to dissociation is taken into account. A significant evolution of the electron scattering anisotropies is observed, in particular in the azimuthal dependence of the MFPADs, characteristic of a photoionization transition between a neutral state of Sigma symmetry and an ionic state of Pi symmetry. This interpretation is supported by a simple model describing the photoionization transition by the coherent superposition of two ssigma and ddelta partial waves and the associated Coulomb phases. (C) 2004 American Institute of Physics.