<title>Structural peculiarities of phosphate glasses for fiber optic applications</title>

Abstract

Alkali phosphate, phosphate-silicate, and phosphate-germanate glasses were studied by means of high-temperature acoustics and Rayleigh-Mandelstam-Brillouin (RMBS) and Raman scattering (RS) spectroscopies. Temperaturetemporal dependences of the ultrasound velocity in the glass melts were measured at temperatures up to 1550 °C. From the RMBS spectra the Landau-Placzek ratio and frequency shifts were found. A theory of the fluctuations freezing at the cooling of the glass melt was applied to separate the contributions of the frozen-in density and concentration fluctuations to the Rayleigh scattering losses. A comparison was drawn with the losses in silica glass. The RS spectra allowed the identification of the constant-stoichiometry groups. The feasibility of the system xNa2O-(40 -x)K20-3OAl2O3-30P205 for the fabrication of low-scattering glasses was ascertained.

Mechanism of Thermal Charge Relaxation in Poled Silicate Glasses in a Wide Temperature Range (From Liquid Nitrogen to Glass Melting Temperature)

“…This fact allows us to conclude that the relevant structural units are not single atoms (ions) but the groups consisting of several atoms. Existence of such groups is confirmed by the data on the Mandelshtam− Brillouin scattering in alkali silicate and other glasses, which demonstrate spectral bands just at 10−15 GHz, and attributed to the midrange structural inhomogeneities 26 revealed in such glasses by the SAXS (small-angle X-ray scattering) method. 27,28 Note that the Mandelshtam−Brillouin scattering in glasses is related just to the characteristic vibrations captured in these midrange inhomogeneities.…”

<title>Nanostructure of glasses: experimental evidence</title>

“…Composition dependencies of Landau-Placzek ratio and light scattering losses relative to SiO 2 (left); density and index (right) for NaPO 3 -Al 2 O 3 glass series31 . Curves are drawn as guides for eye.…”