OPTICAL-PROPERTIES OF DENSIFIED SILICA GLASSES

Densities, refractive indices, and IR (reflection and absorption) spec tra are systematically investigated for permanently densified silica g lasses. The linear relation between refractive index and density of th e densified silica glasses is observed in a wide range of densities. T he frequency of the IR band near 1100 cm(-1) is found to decrease line arly with increasing density. The Gruneisen constants are evaluated wi th IR spectra. The optical properties of densified silica,glasses are discussed with the proposed relations linking density, refractive inde x, Gruneisen constant, and mean polarizability. The difference in refr active index of permanently densified and in situ compacted glasses wi th the same density is due to different Gruneisen constants. (C) 1998 Elsevier Science B.V. All rights reserved.