GROWTH OF LIB3O5 SINGLE-CRYSTALS IN THE LI2O-B2O3 SYSTEM

The Li2O-B2O3 system was investigated with a view to the determination of the most suitable concentration region for growth of LiB3O5 crysta ls of optical quality. The saturation temperature of the solutions for the LiB3O5 phase has been determined by the slow cooling method of hi gh-temperature solutions. The dynamic viscosity of the solutions in th e concentration region of the LiB3O5 phase has been measured. Experime nts to obtain LiB3O5 crystals from the solutions in this region were p erformed. The data obtained on the properties of the solutions as a re sult of crystal growth experiments from these solutions make possible a choice of the most suitable region of compositions of the solutions in Li2O-B2O3 system for growth of LiB3O5 single crystals. This concent ration region is from about 72 to about 82 wt% LiB3O5 in the solution. In this region the viscosity has relatively low values and it varied only slightly with the concentration. The crystals grown there were fr ee from inclusions and cracks, and the growth rates were suitable for practical obtaining of LiB3O5.