Effect of heating on dissipation of mechanical energy in fused silica fibers

We present a study of the change of the Q-factors (Q's) of the bending modes of fused silica fibers caused by the heating of the fiber to 330 deg. C and its subsequent cooling. Irreversible dependence of Q's on the temperature was observed. Baking the fiber resulted in the increase of Q's in a limited temperature range. Room temperature Q's did not vary after the baking of the fiber. We assume that these changes are caused by desorption of water molecules from the fiber surface. The possible mechanism of losses associated with adsorbed water is analyzed