Chalcogenide glasses of As
2Se
3-xTe
x(

) were fabricated with special care to avoid traces of oxygen, using very pure raw materials. From part of these materials, special plates were made, and from the rest fibers were pulled. From transmittance measurements, the existence of absorption bands was shown, corresponding to the presence of small crystallites of As
2O
3. The attenuation in the infrared of these plates increased from 14 dB/m for As
2Se
3to 29 dB/m for As
2Se
0.5Te
2.5. Conversely, a decrease of microhardness V
Hwas observed. The attenuation of CO
2laser light (

m) transmitted through the pulled fibers was measured as a function of the Te(

) content. and an increase of the attenuation was observed from 18.1 dB/m for As
2Se
3to 66.7 dB/m for As
5Se
1.5Te
1.5. The surface of each fiber was examined in the scanning electron microscope and an increase of the defects (e.g., crystallites) when the Te content was increased, was observed. These defects (crystallites) are the main factors for finding an increase in the absorption in IR.