Time resolved thermal lens measurements of the thermo-optical properties of glasses at low temperature down to 20 K

In the present paper we extended the capability of the thermal lens spectrometry (TLS) to measure D, K and ds/dT of two oxide glasses, the low silica calcium aluminosilicate (LSCAS) and the soda-lime, as a function of temperature, between 20 and 300 K. The main contribution for the strong increase of ds/dT values as a function of temperature for LSCAS and soda lime glasses is a consequence of the increase in the electronic polarizability coefficient with temperature. The results of this work indicate that time resolved TL can be advantageously used to determine the TOP of glasses at low temperatures bringing new possibilities for experiments in a wide range of optical materials.