Effect of stirring on striae in glass melts

Chemical striae have often negative effect on the glass properties, and hence, elimination of striae has been a key issue in glass science and technology. To produce highly homogeneous glasses, it is necessary to stir melts during the melting process. To explore the physical origin of the stria elimination during stirring, and to optimize the homogenisation process, both simulations of striation and homogenisation experiments are performed. The results show that stirring broadens the stria size distribution in the melt through conversion of larger striae into smaller ones. Only the striae with a size below half the diffusion length in the melt can be eliminated during the melting process. Stirring itself does not homogenise the melt, but enhances the stria elimination rate by generating small striae.