Phase transition of Li2O-Al2O3-SiO2 glass-ceramics used for optical fiber ferrule

Phase transitions of Li2O-Al2O3-SiO2 based glass-ceramic materials, which can be used for the fabrication of optical fiber ferrule, were studied by means of DTA, XRD, SEM and CTE. The temperature range of the phase transition studied was 850-1270°C. The results show that the metastable β-quarts s.s first precipitates at 870°C and translates into the β-spodumene s.s, the prominent crystal phase, at higher temperature. Increasing the heat-treatment temperatures from 900°C to 1000°C and prolonging the time, the size of the granule changes little. With the transition of β-quarts s.s. to the β-spodumene s.s, the CTE of the material increases greatly and then it gradually stabilizes when the transition is completed. During the heat-treatment of the material at 1150-1270°C, the granule size grows and the glass phase increases quickly. At the same time, the CTE of the material increases too.