title: Mid-range structure of niobium-sodium-phosphate electro-optic glasses.
abstract: The mid-range structure of glasses of the glass-forming system xNb(2)O(5)-(60 - x)P(2)O(5)-40Na(2)O, with x varying from 0 to 40, has been investigated by Raman spectroscopy and electro-optical Kerr measurements. It was found that the mid-range inhomogeneities in the glasses under study vary with x and their compositions and structures dramatically differ from the gross glass composition. It is shown that inhomogeneities with the 8NaNbO(3) + (Nb(2)O(5)·P(2)O(5)) composition are responsible for the electro-optical sensitivity of the glasses. The electro-optical structural elements of the inhomogeneities of this type are assumed to be fragments of the quasicubic lattice of crystalline NaNbO(3) demonstrating a rather high electro-optic Kerr coefficient. The obtained results are discussed in terms of the concepts of constant stoichiometric groupings and crystal motifs.
authors.affiliation: St. Petersburg Academic University, 195220 St. Petersburg, Russia.
authors.forename: A A
authors.initials: AA
authors.lastname: Lipovskii
authors.forename: D K
authors.initials: DK
authors.lastname: Tagantsev
authors.forename: I E
authors.initials: IE
authors.lastname: Apakova
authors.forename: T S
authors.initials: TS
authors.lastname: Markova
authors.forename: O V
authors.initials: OV
authors.lastname: Yanush
authors.forename: M G
authors.initials: MG
authors.lastname: Donato
authors.forename: L
authors.initials: L
authors.lastname: Sirleto
authors.forename: G
authors.initials: G
authors.lastname: Messina
authors.forename: G C
authors.initials: GC
authors.lastname: Righini