Thermal-optical properties of Ga : La : S glasses measured by thermal lenstechnique

In this work the quantitative theoretical treatment for two beam mode misma tched thermal lens spectrometry is applied to investigate the thermo-optica l properties of chalcohalide (chalcolgenides and halides mixture) glasses. For the three kinds of glass studied the thermal diffusivity varied between 2.5 and 2.7 x 10(-3) cm(2) s(-1). Using these results and supposing Dulong -Petit specific heats we estimated the thermal conductivity and temperature ratio of optical path length (ds/dT) and temperature coefficient of refrac tive index (dn/dT). All samples had positive ds/dT(similar to 3.3 x 10(-6) K-1) and negative dn/dT (similar to -26 x 10(-6) K-1). The difference betwe en these parameters and the change of signal are consequences of the expans ion coefficient (13 x 10(-6) K-1) and refractive index (n similar to 2.6) o f chalcohalides. (C) 1999 Elsevier Science B.V. All rights reserved.