Because of its unusual properties, singlet oxygen can persist for over an hour at room temperature, in isolation. Because of differences in their electron shells, singlet and triplet oxygen differ in their chemical properties. Singlet oxygen is highly reactive.
Singlet oxygen is usually generated with a photosensitizer pigment. The damaging effects of sunlight on many organic materials (polymers, etc.) are often attributed to the effects of singlet oxygen. In photodynamic therapy, singlet oxygen is produced to kill cancer cells.[1]