**4. Textile applications**

Photochromic compounds as the ones represented in this chapter are commercially available from a number of suppliers, such as: Sigma Aldrich, PPG Industries and James Robinson. So far, virtually all application techniques have been investigated in efforts of functionalizing the textile fiber with photochromic systems. Some application methods have been proven advantageous over the other, such as embedding into the polymer matrix in the spinning phase of the "man-made" fibers (polypropylene). Other processes may include dyeing and screen printing, which are considered more appropriate since the demand on photochromic textiles is limited to piece garments, rather than to batch production (Billah, 2008; Canal, 2008; Nelson, 2002).
