The basic arrangement of gramophone discs has not changed throughout their history. What has changed is the size of the discs, the speed at which they are played and the methods and materials used in their manufacture. Various materials have been used in the manufacture of gramophone discs. Another type of disc is the instantaneous recording disc which consists of a metal substrate, usually aluminium, with a layer of cellulose acetate or cellulose nitrate overlaid on one or both sides. Gramophone discs have recently been all but superseded by the new technology of the compact disc.
All materials degrade over time.
We cannot control this inevitable deterioration, but we can control how fast it happens. Certain materials are susceptible to deterioration in particular ways just because of their properties, and other materials deteriorate as a result of particular environmental conditions. Cellulose nitrate and cellulose acetate are chemically unstable and give off nitric and acetic acid respectively as they degrade. Eventually the disc will deteriorate so that it cannot be played. Instantaneous recording discs consist of a very thin layer of plastic over a metal substrate.