Optical Brightener TBO is the trade name for the chemical: Bis(tert-butyl benzoxazolyl) thiophene. It is highly effective in polymer substrates such as engineering plastics, PE, PC, PVC, PS, ABS, and PP. In plastics it imparts excellent brightness. It can be used in lacquers, paints, and coating.  In these applications it is used to counteract the yellowness of coatings and provide a whiter appearance. It has excellent resistance to heat, exceptional whitening properties, good light fastness and low volatility. Optical Brightener TBO can be used alone or in a variety of blends and combinations with other additives, including antioxidants, processing stabilizers, and light stabilizers.