Structural characteristic of Na2OP2O5GeO2 glass systems

Spectroscopic properties and thermal stability of Er3+-doped germanate–borate glasses

“…The spectroscopic properties of rare earth ions in simplex oxide hosts, for instance borate, silicate, phosphate, germinate and tellurite have been previously investigated. In recent years, studies concerning two or more kinds of oxide hosts for example tellurite-borate [7][8][9], germanate-tellurite [10][11][12], tellurite-phosphate [13][14][15], germanate-silicate [16][17][18] and germanate-phosphate [19] have been reported for the optical properties of rare earth ions incorporated in these glass matrices can easily be modulated by varying the ratio of two kinds of oxides. To our best knowledge no research on spectroscopic and laser properties of trivalent erbium in germanate-borate glass has been performed.…”

Homogeneous Ag2O–2P2O5–CaO–GeO2 glass formation, structural and in vitro studies

“…Still in mix cation-phosphate glasses it is difficult to assign with accuracy the contribution of the bands under the wide envelope. The band centered at ∼530 cm −1 could be given by ı(O P-O) corroborated with s (Ge-O-Ge) modes [4,23]. (b) FT-IR absorption band placed at ∼1040 cm −1 in x = 0 sample is shifted to smaller wave numbers, being centered at ∼1020 cm −1 for x = 1 mol% Ag 2 O.…”

“…The FT-IR spectrum of the glass matrix exhibits in the lower wave number domain bands that are due to overlapping of vibration modes coming from both phosphate and germanate structural units as follows: the broad bands centred at ∼500 cm −1 may be assigned to fundamental frequencies of PO 4 3− or the harmonics of ı(O P-O) [4,5,8] but also could be attributed to the symmetric stretching modes of Ge-O-Ge bonds associated with three-membered GeO 4 rings in the glass network [23,24]. The wide band found at ∼760 cm −1 is assigned to the symmetric stretching vibration of P-O-P bonds occurring in ring type groups associated with Q 2 units [4,5].…”

“…We may consider the band from ∼476 cm −1 as a contribution from stretching modes of Ge-O-Ge bonds associated with three-membered GeO 4 rings [23,24] but also from the characteristic Ag-NBO (non-bridging oxygen) bond vibration. It is well known that in oxide glasses the metal oxygen interaction give rise to a single far infrared (below 500 cm −1 ) absorption assigned to the vibration of the metal cation in its oxygen cage.…”

“…The broad band centered at ∼350 cm −1 is assigned to both symmetric stretching of Ge-O-Ge bonds associated with four-and three-membered GeO 4 rings [23,24] and also to pendent PO 2 bending and in chain O-P-O bending motion [8]. Raman band centered at ∼550 cm −1 is assigned to both symmetric stretch of P-O-P bond and Ge-O-Ge bending modes associated with GeO 4 tetrahedral ring strain [5][6][7]23,24].…”