Glass Wool — Phase Transitions

Glass Wool is often used for the insulation of houses and heating pipes. The STA measurement shows three mass-loss steps below approx. 600°C, which are due to the evaporation of humidity and the burn-up of organic binder. The latter can be seen from the strongly exothermic DSC signal in this temperature range. The step in the DSC signal at 728°C with an increase in the specific heat of 0.41 J/(g*K) is due to the glass transition. The exothermic DSC peak at 950°C with an enthalpy of -287 J/g is due to crystallization; the endothermic effects between approx. 1050°C and 1250°C with an entire enthalpy of 549 J/g show the melting. The slight mass changes above 700°C are most probably due to oxidation and evaporation of impurities.