Raman spectroscopy has been used to characterize the structure of glas
s fibers with diameters as small as 3 mu m. A special sample holder, w
hich enables the laser beam to strike the transverse surface of the fi
ber bundles and to probe structural variations along the longitudinal
direction, was designed. Structural variations in multi-component sili
cate glass fibers were studied as a function of fiber drawing conditio
ns and different annealing temperatures.