A sensor for optical response to measure the environmental acidity was prepared with four- organic molecules mixture: p- dimethylaminazobenzene (dimethyl yellow), (o-((p-(dimethyla- min)phenyl)azo)benzoic) acid (methyl red), α,α Bis (6 bromo 5 hydroxycarvacryl) a hidroxi -o- toluene g sulphone (bromothymol blue), and α-hidroxi-α , α-bis (5 hydroxycarvacryl)-p-toluensulphonic acid (timol blue), which were incorporated to the vitreous network through a sol-gel process using tetraethylortosilicate (TEOS) and methyltrieto- xide of silicon (ME3S) as precursors; the pH ranged from 1 to 10. The films were deposited over a small pieces of soda lime glass, and the optical characterization of films was carried out by absorption spec- trometry using a Perkin Elmer Lambda 11. The Photostability surveys of the samples were performed with an ultraviolet lamp of 10W at dif- ferent exposure times, after that they were immersed in different acid, aqueous and alkaline environments (NaOH 0.5M, Na2CO3 0,1M) to probe adherence and chemical resistance properties. The Sensor obtai- ned is sensitive to pH variations both in liquids as in moist gases, in addition, it is a reversible and stable sensor to chemical changes.