P42. Application of chemometrics method and constant stoichiometry groupings concept to the Raman spectra of lead metaphospate — TeO2 glasses

Inna E. Marusina1, Olga Yu. Derkacheva1, Vladimir K. Goncharuk2, Irina G. Maslennikova2, Irina G. Polyakova3, Anatolii V. Anan'ev4, Leonid V. Maksimov4, Tatiana S. Markova1, Oleg V. Yanush1

1St. Petersburg State Technological University of Plant Polymers, Russia

2Institute of Chemistry of Far-Eastern Branch of Russian Academy of Sciences, Vladivostok, Russia

3Institute of Silicate Chemistry, Russian Academy of Sciences, St. Petersburg, Russia

4Research and Technological Institute for Optical Material Science, St. Petersburg, Russia

Lead metaphospate — TeO2 glasses in the whole range of glass content were first obtained and their properties (refractive index, density, glass transition temperature and light scattering losses and others) were determined. Based on the vibrational spectroscopy data a new approach has been proposed to investigate the interactions of initial oxides in melts resulted in so-called constant stoichiometry groupings (CSG) formation. Vibrational spectra of glasses are interpreted as a superposition of relatively small number of unchangeable spectral forms belonging to CSGs. For lead metaphospate — TeO2 glass series, CSGs extracted from Raman spectra analysis are PbO×P2O5, TeO2×2PbO×2P2O5, TeO2×PbO×P2O5, 2TeO2×PbO×P2O5 and TeO2.

In this work MVDA has been applied as the independent mathematical tool to decompose Raman spectra of glasses and reveal the number of PSCs. It is shown that application of factor analysis results in five PSCs that confirms our data obtained from the concept of CSGs. These principal spectral components were selected taking into account dependences of ERV parameter and eigenvalues on the number of PSCs.

The composition dependences of the concentrations of the CSGs have afforded an opportunity to explain and calculate the compositional dependences of refractive index and density of glasses in a good agreement with experimental data and even to predict refractive index and density values for vitreous TeO2 and PbO×P2O5. The Raman spectra analysis developed allowed also predicting of the existence of unknown compounds. The CSGs TeO2×2PbO×2P2O5, TeO2×PbO×P2O5, 2TeO2×PbO×P2O5 discovered using Raman spectroscopy data exclusively has been verified by X-ray powder diffraction of crystallized glasses.

The concept of CSG opens the way to elaboration of low scattering glasses as candidates for Raman amplifiers. It is shown that glasses of lead metaphospate - TeO2 series containing small additive of tellurium dioxide are of interest to photonics technology. These glasses are uncolored, weather-resistant, the level of light scattering losses of glasses is comparable with that in fused silica. The minimal optical losses give us reasons to consider these glasses as an efficient active medium for Raman fiber lasers and amplifiers. In the case of using excitation laser source at 1480 nm the Raman amplifier range will correspond to wavelength between 1500 and 1790 nm.