Melts in the composition range of bioactive glasses have their liquidus temperatures within or close to working range. Additionally, bioactive glasses show a strong tenancy to crystallisation due to their composition. Thus many bioactive glass compositions are unsuitable for demanding working procedures such as fibre drawing. In this work we discuss the suitability of different methods for measuring liquidus temperature of bioactive glasses. Thermal analysis was used, and complemented by sintering curves as given by hot stage microscopy. Hot stage microscopy could be used to measure liquidus also when the thermal effect associated with liquidus was low and consequently the DTA was not suitable. Liquids of some glasses was measured with optical microscopy for samples heat treated in a gradient furnace.
