DSC and non-linear optical monitoring of the glass transitions in GeO2–PbO doped by erbium

Two methods of phase transition detection — non-linear optical based on optical poling (second harmonic generation) together with traditional, calorimetrical, Differential Scanning Calorimetry are compared. The investigations are performed near glass transition and melting point. As examples germanate GeO2–PbO glasses doped by Er+3 ions are chosen. It is demonstrated that although both methods give an evidence of the transitions the non-linear optical one is much more sensitive. A short description of the experimental set-up for the optical measurements and physical aspects of the method are given.