What is crazing in relation to glass?

Crazing in relation to glass refers to the development of a network of fine cracks on the surface, which can occur due to rapid cooling. When glass is formed, it is often subjected to high temperatures during the melting and shaping process. If the glass cools too quickly, it can lead to stress within the material because of the differences in temperature across its surface and interior. As this stress increases, small cracks may begin to form, resulting in the characteristic pattern of crazing. This phenomenon can affect the aesthetic appearance and structural integrity of the glass, particularly in glassware or artistic pieces where visual clarity is important.

The other options presented describe different processes not directly related to the phenomenon of crazing. The formation of bubbles pertains to issues during the melting stage, while aging would involve changes in physical properties over time rather than immediate transfer of temperature stresses. The melting down of glass simply refers to the process of heating glass until it becomes liquid, again not related to the surface cracking associated with crazing.