Some embodiments include methods of forming patterns. A block copolymer film may be formed over a substrate, with the block copolymer having an intrinsic glass transition temperature (Tg,O) and a degradation temperature (Td). A temperature window may be defined to correspond to temperatures (T) within the range of Tg,O≦T≦Td. While the block copolymer is in the upper half of the temperature window, solvent may be dispersed into the block copolymer to a process volume fraction that induces self-assembly of the block copolymer into a pattern. A defect specification may be defined, and the process volume fraction of solvent may be at level that achieves self-assembly within the defect specification. In some embodiments, the solvent may be removed from within the block copolymer while maintaining the defect specification.