The nonlinear optical process which permits the optical preparation of centrosymmetric materials for frequency doubling is described in terms of an orientational hole-burning effect induced through non-zero E(3) resonant six-wave mixing. A permanent all-optical poling is achieved by seeding preparation under backward and forward geometries in an azoaromatic acrylic copolymer. The frequency doubling second order susceptibility reaches 90 pm/V, as large as using the more classical corona poling technique. This offers a new molecular engeneering route to the control and optimization of phase-matched oriented microstructures for frequency conversion and also for electro-optic organic devices.