Fluorophosphate glass is a class of optical glasses composed of metaphosphates and fluorides of various metals. It is a variant of phosphate glasses. Fluorophosphate glasses are very unusual in nature. Fluorophosphate glasses have ultra-low theoretical loss of 0.001 dB/km, longer fluorescent lifetime of rare earths, lower coefficient of thermal expansion of ~13×10−6/°C. Exotic dopants like fullerenes and quantum dots can be employed. Tungsten-doped tin-fluorophosphate glasses (SnO-SnF2-P2O5) can be used for hermetic sealing of organic light-emitting diodes and other devices.