A modified prism method has been used for the Refractive Index (RI) determi
nation of lead scandium tantalate Pb2ScTaO6 (PST) single crystals with pero
vskite structure. The crystals are obtained by the High Temperature Solutio
n Growth (HTSG) method. The RI values of PST crystalline prism are measured
with error of +/- 2 x 10 (- 3) in the temperature range 0-40 degreesC. A j
ump around 15 degreesC is observed in the temperature dependence of RI, whi
ch is explained by the presence of the diffuse paraelectric (PE)-ferroelect
ric (FE) phase transition. Transmission spectra (TS) in the same temperatur
e range are presented. (C) 2001 Elsevier Science B.V. All rights reserved.