In the first part of this paper, the importance of annealing in the process of glass manufacturing is stressed. The need to submit the glass to thermal treatment so that its general properties, or some specific one, do not experience important variation is emphasised.. This is followed by a brief description of the origin of permanent tensions in glass, in accordance with the most widely accepted theories. Due to its simplicity, an example is given of the tensions created in a parallel plane glass plate on cooling it according to a simple law. The next section described the logical steps and most basic parameters to be taken into account when experimentally programming the annealing cycle of a certain glass article. Finally methods are included which are of great interest in the calculation of the annealing curve and which are those proposed by Redston-Stanworth, Corning glass works and the czecholovakian glass institute. To facilitate the application of these methods the most well known expressions of temperature viscosity interpolation are listed.
