ACOUSTIC CHARACTERIZATION OF SILICA GLASSES

Acoustic characterization of doped silica glasses with a GeO2, P2O5, F , TiO2, Al2O3, or B2O3 dopant having different concentrations is prese nted. Quantitative measurements were performed with a 225-MHz line-foc us-beam scanning acoustic microscope. The acoustic velocity variation due to different dopant concentrations is given. It has been found tha t the Al2O3 dopant increases, but the other dopants decrease, the acou stic velocity as compared with that of the pure fused silica. We have also found that the fractional change in acoustic velocity is greater than that in refractive index for a given dopant concentration.