Glasses are commonly synthesized by cooling melts at a rate sufficient to prevent the nucleation of substantial amounts of crystalline phases. In the limit, high cooling rates no longer prevent crystallization. In some of these cases, elimination of container-melt-induced nucleation by using containerless processing (also called levitation) significantly extends the glass forming composition range. Containerless methods also eliminate contamination allowing the preparation of high-purity materials that can be used to benchmark properties & structure. This article briefly reviews the application of containerless methods to several types of glass. Some examples of glasses formed using containerless techniques are presented & discussed in the context of developing materials. A short commentary on specific issues that relate to the use of containerless processing is presented.
