Acoustic properties of silica glass doped with fluorine

The acoustic properties, viz., longitudinal and shear wave velocities, and the density, were measured with high accuracy for silica glass specimens doped with different concentrations of fluorine, and further, their leaky surface acoustic wave (LSAW) velocity and elastic constants were calculated from the above measured values. The temperature dependences of the acoustic properties were also measured around room temperatures, viz., 20.0–26.0 °C. Remarkable changes in the acoustic properties caused by doping fluorine into vitreous silica have been obtained. As compared with vitreous silica glass, the longitudinal velocity, shear velocity, LSAW velocity, and the density of silica glasses doped with fluorine decrease with −66 (m/s)/mol%, −50 (m/s)/mol%, −43 (m/s)/mol%, and −2.4 (kg/m3)/mol%, respectively. Since these acoustic properties are varying linearly with fluorine concentration, and since they exhibit higher sensitivities to the variation of fluorine concentration than do the optical properties, the fluorine concentration dependences of the acoustic properties obtained in the present study can be widely used in the ultrasonic characterization of glass materials and optical waveguides doped with fluorine.