We report a generic phenomenon in the ordering of block copolymer thin films, wherein the morphology spontaneously antialigns with respect to film discontinuities during thermal annealing. The aligned nearedge region propagates further from the edge with increased annealing time and temperature, while also being responsive to heating rate and applied stress fields. This effect is ascribed to a combination energetic preference for morphological orientation at boundaries as well as stress relaxation of the polymer film as it creeps orthogonal to film edges.