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The glassy state of matter is common to all types of materials, be they metallic, inorganic or polymeric, for example. The transformation from an equilibrium liquid state to a nonequilibrium glassy state is usually achieved by cooling at a rate sufficiently rapid for crystallization to be inhibited. For metals, this generally requires cooling rates of the order of millions of degrees per second, whereas, for polymers that can crystallize, a glassy state can be achieved with cooling rates of only hundreds of degrees per second. Furthermore, for atactic polymers the irregularity of the chemical structure prevents crystallization and results naturally in an amorphous glassy state. Cooling is not the only way in which a glassy state can be achieved, though. The application of high pressure is another method, though it is rather rarely used for reasons of experimental difficulty and danger. On the other hand, an alternative method that is very commonly used is by means of a chemical reaction, and in particular the curing reaction of a thermosetting polymer. In the present paper we concentrate on the glass transformation process by these two commonly applied methods, namely cooling from the equilibrium liquid-like state and vitrification during the crosslinking reaction of a thermosetting polymer. The glassy state is characterized by a lack of long range order, and is also referred to as an amorphous state. This does not, however, mean that there is no discernible structure of the glass; on the contrary, there is a structure to the glass, which can be quantified in respect of its short range order, and this structure is dependent on the way in which the glass was formed. A good example of this is the preparation of densified glasses by cooling from the melt state to the glassy state under high pressure and then releasing the pressure; the density, and other properties, of the glass formed under pressure in this way is greater than, and remains greater than, that of the glass formed from the same melt by cooling at atmospheric pressure. The fact that the structure of the glassy state depends on the way in which the glass was formed is important, because the properties of the glass are, in their turn, dependent on the structure. A further important characteristic of the glassy state is that it is a non-equilibrium state. This was first recognized by Simon (Simon, 1931) the best part of a century ago, who proposed that, on cooling the equilibrium liquid at constant pressure, a transformation to a glass takes place at a temperature, known as the glass transition temperature, Tg, when the timescale for molecular rearrangements, which increases as the temperature decreases, becomes longer than that available corresponding to the imposed cooling rate. An immediate consequence

The Use of Matlab in the Study of the Glass Transition and Vitrification in Polymers