Three distinctly different microstructures of silica(as quartz and crystobalite), alumina, enstatite and celsian, were found to develop in a 60Si02-20MgO-10Al203-10BaO glass ceramic. At 1010 deg C, growth of wormy fibrillar crystals was observed, indicating that crystal growth was diffusion controlled. At the intermediate temperature of 1080 deg C, a coarse cellular microstructure developed with multiple spherical particles nucleated on their surfaces and in the surrounding glass. At 1200 deg C, the glass crystallises in a denderitic morphology but the dendrites were actually fragmented into multiple cube-shaped enstatite crystals, indicating a transition to interface-controlled growth. The crystals coarsen with time but maintain their order along the dendrite skeletons.
