This invention relates to a process to polymerize olefins comprising contacting a catalyst or catalyst system with olefin(s) in the presence of a fluorocarbon at a temperature above the onset melting point of the polymer. This invention also relates to a solution process to polymerize olefins comprising contacting a catalyst or catalyst system with olefin(s) in the presence of a fluorocarbon at a temperature above the onset melting point of the polymer.