2 amino- 3 hydroxy pyridine react with a singlet oxygen the absorbance (at 318nm) decreases. How does the singlet oxygen effects its absorbance

I know 2 amino- 3 hydroxy pyridine is a singlet oxygen quencher.  can any one tell me after reacting with singlet oxygen how does it actually reduce the absorbance or why? 

23 January 2017 1,250 3 View