Temperature dependence of the thermo-optical properties in fragile tellurite glasses

In this work the thermal lens spectrometry (TLS) in function of the temperature was applied in TeO/sub 2/-Li/sub 2/O (TL) and TeO/sub 2/-Li/sub 2/O-TiO/sub 2/ (TLT) tellurite glasses in order to determine their thermo-optical properties. By fitting the thermal lens transient signal the parameter /spl theta/ can be obtained, which is proportional to (-P/sub abs/ds/dT) and is related to the thermal lens signal amplitude, where P/sub abs/ is the absorbed power. The ds/dT signal inversion related in this work is the first experimental observation of this phenomenon.