Highly oriented tungsten-bronze K(SrBa)(2)Nb5O15 (KSBN) thin films have been fabricated by a chemical solution deposition method. Alkoxy-derived K(Sr0.5Ba0.5)(2)Nb5O15 (KSBN50) thin films directly crystallized into a tetragonal tungsten-bronze phase on fused silica, MgO(100), and Pt(100)/MgO(100) substrates with c-axis preferred orientation at 700 degrees C by optimizing the processing conditions. Ferroelectric KSBN50 thin films on Pt(100)/MgO(100) exhibited the diffuse-phase transition and typical relaxor-type dielectric behavior, which are characteristic properties along the c-axis of the tungsten-bronze (Sr,Ba)Nb2O6 crystal. The KSBN thin films synthesized on fused silica and MgO(100) showed high transparency over a wide wavelength range. The propagation modes of the synthesized KSBN thin films were characterized by the prism coupling method. The values of their refractive indices in TE and TM modes were 2.27 and 2.25, respectively. (C) 2008 Elsevier B.V. All rights reserved.