Organic photovoltaics are a low cost alternative to existing photovoltaic materials and their efficiency is steadily increasing towards the point where their cost per Watt is competitive. In order to improve the device efficiency, it is essential to modify the nanoscopic morphology of the active layer by annealing. However the morphology of the phase separated regions of the most commonly used materials, P3HT and PCBM, within the active layer is still not completely understood. In previous NR studies we revealed the vertical structure of the active layer, and we have recently acquired SERGIS data proving that we can now measure characteristic length scales within the active layer of these devices. Therefore we wish to use SERGIS to probe the morphological changes caused during thermal and solvent annealing. This understanding will be vital for device efficiency optimization.