This paper will thus give an overview of methods to reduce efficiently the Rayleigh scattering loss via the fictive temperature in silica-based optical fibers. We will first recall what the concept of fictive temperature T(f) is and its limitations in section 2. We will see that both Raman and IR spectroscopy can be used to determine T(f) (Section 3). Section 4 will thus give some examples of T(f) profiles measured in optical fibers manufactured in different conditions. Finally, section 5 will present the main approaches to reduce Rayleigh scattering loss in silica-based fibers via a reduction of T(f). (C) 2011 Elsevier Ltd. All rights reserved.