Dioxane has been purified by distillation to remove the common impurities such as acetaldehydes,ethylene acetal,acetic acid,water and peroxides [1,2].The impurities mainly come from its synthesis steps via the dehydration of ethylene glycol with sulfuric acid or the heating of ethylene oxide (or bis(β-chloroethyl)ether) with NaOH.Compared to distillation,melt crystallization has advantages in energy efficiency,which has recently attracted many researchers due to increasing environmental and energy concerns [3].In this study,the melt crystallization of dioxane was investigated by morphological investigation.By adding small amounts of polymer solutes,the crystal morphology of dioxane can be traced from the examination of pore structures.The spacing between dioxane crystals follows the simple prediction based on Fick’s law and materials balance to a certain extent,which was proposed by Rohatgi and Adams [4].The spacing between the dioxane columns,L,is L=(8D△T)0.5F-0.5 where D is the diffusion coefficient related to concentration terms,ΔT is the supercooling between columns,and F represents the freezing rate.This detailed investigation on crystal morphology will provide basic understanding on the melt crystallization process of dioxane.Furthermore,the morphological understanding can be used for the preparation of porous polymers [5-7].