Synthetic Metals 155 (2005) 434–438 Optical diffraction of second harmonic generation in SrBi 2 (Nb 0.7 V 0.3 ) 2 O 9 in the SrO–Bi 2 O 3 –0.7Nb 2 O 5 –0.3V 2 O 5 –Li 2 B 4 O 7 glass system B. Harihara Venkataraman a , K.B.R. Varma a,∗ , Vincent Rodriguez b , Mario Maglione c , J. Etourneau c a Materials Research Centre, Indian Institute of Science, Bangalore, India b Laboratoire de Physico-Chimie Moleculaire, UMR 5803 CNRS – Universite, Bordeaux, France c Institute for Condensed Matter Chemistry of Bordeaux (ICMCB) – Universite, Bordeaux 1, France Available online 4 November 2005 Abstract Transparent glasses in the system (100 - 3x)(Li 2 O–4B 2 O 3 )–x(SrO–Bi 2 O 3 –0.7Nb 2 O 5 –0.3V 2 O 5 ) (where x = 10, 30 and 50, in molar ratio) embed- ded with nanocrystallites of SrBi 2 (Nb 0.7 V 0.3 ) 2 O 9 exhibited intense second harmonic signals in transmission mode when exposed to IR laser light at λ = 1064 nm. The second harmonic waves were found to undergo optical diffraction. The origin of optical diffraction in these samples was attributed to the self organised structures of fine crystallites of submicrometer size that were inscribed in-situ by the IR laser radiation. Laser Raman studies confirmed these crystallites to be vanadium doped strontium bismuth niobate. © 2005 Elsevier B.V. All rights reserved. Keywords: Melt processing; Crystalline/glass interfaces; Transmission electron microscopy; Glass transitions; Nonlinear optical methods 1. Introduction In recent years, a variety of glass ceramics were investigated for various physical properties which include dielectric, pyroelectric, ferroelectric and nonlinear optic [1–3]. The basic interest on glasses comprising nano/microcrystallites of polar materials stemmed from the large third order nonlinear optical effects that were exhibited by TeO 2 based glasses [4]. We have been examining the possibility of growing ferroelectric crystals belonging to the Aurivillius family of layered ferroelectric oxides of the homologous series [Bi 2 O 2 ] 2+ [A n-1 B n O 3n+1 ] 2- , in strontium borate (SrB 4 O 7 ) and lithium borate (Li 2 B 4 O 7 ) (LBO) glass matrices [5,6] for multifarious applications. It was recently, reported in the literature that a partial replacement of niobium in SrBi 2 Nb 2 O 9 (SBN) (which is an n = 2 member of the above series) by pentavalent vanadium has improved its physical properties [7]. In order to explore the possibilities of employing glass nano/microcomposites for nonlinear optic based devices, SrBi 2 (Nb 0.7 V 0.3 ) 2 O 9 nano/microcrystals were grown in trans- parent Li 2 B 4 O 7 glass matrix, though there is a considerable ∗ Corresponding author. Tel.: +91 80 309 2915; fax: +91 80 360 0683. E-mail address: kbrvarma@mrc.iisc.ernet.in (K.B.R. Varma). mismatch in the refractive indices of these two materials. In this paper, we report the experimental details pertaining to the fabrication of glass composites and evolution of vana- dium doped SBN (SrBi 2 (Nb 0.7 V 0.3 ) 2 O 9 ) phase in the system (100 - 3x)(Li 2 O–4B 2 O 3 )–x(SrO–Bi 2 O 3 –0.7Nb 2 O 5 –0.3V 2 O 5 ) (where x = 10, 30 and 50, in molar ratio) along with their structural and nonlinear optical properties. 2. Experimental Glasses of different compositions in the system (100 - 3x)(Li 2 O–4B 2 O 3 )–x(SrO–Bi 2 O 3 –0.7Nb 2 O 5 –0.3V 2 O 5 ) (where x = 10, 30 and 50, in molar ratio) were fabricated via the melt quenching technique. Well mixed powders containing appro- priate amounts of reagent grade SrCO 3 , Bi 2 O 3 , Nb 2 O 5 ,V 2 O 5 , Li 2 CO 3 and B 2 O 3 were melted in a platinum crucible at 1423 K for 0.5 h in an electric muffle furnace (LENTON). A pair of steel blocks were used to quench the melts into 1mm thick plates. These plates were annealed at 523 K (for 6 h) which is well below the glass transition temperature to anneal out the ther- mal stresses. The glassy state of the as-quenched samples was established by subjecting the powders (weighing ≈ 20 mg) to differential thermal analyses (DTA) in the 300–1273K temper- ature range. A uniform heating rate of 10 K/min was employed 0379-6779/$ – see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.synthmet.2005.09.031