The internal friction of partly crystallized Li2O.‐2.75 SiO2 glass fibers, containing a maximum of 78% lithium disilicate crystals, was measured by the torsion pendulum technique. The following changes in the internal friction were observed with increasing crystallization: (1) The low‐temperature peak, generally attributed to the stress‐induced diffusion of alkali ions, decreased continuously in height and shifted to higher temperatures at the higher crystal contents, (2) the intermediate‐temperature peak decreased continuously in height, and (3) a new relaxation, which first appeared as an inflection in the background of the glasses which had been nucleated at 500° C. without any crystallization, became a well‐defined peak in the partly crystallized fibers. It is suggested that this new relaxation may be an indication of the early stages of nucleation. Possible explanations are given for the high‐temperature relaxation observed in the partly crystallized glasses.