LOW-COST, WEATHER-RESISTANT PHOTOCHROMIC THIN FILMS BY THE SOL-GEL PROCESS

SILVER HALID CONTAINING GLASSES ARE THE MOST SATISFACTORY PHOTOCHROMIC MATERIALS WHICH POSSESS (A) A LARGE TRANSMITTANCE CHANGE FROM 20-30% TO 80-90% WITH AND WITHOUT DIRECT SOLAR ILLUMINATION; (B) FAST DARKENING AND BLEACHING; (C) FREE OPTICAL FATIGUE; (D) GOOD CHEMICAL DURABILITY. HOWEVER, FABRICATION OF LARGE AREA OF SILVER HALIDE PHOTOCHROMIC GLASSES SUFFERS FROM RELATIVELY HIGH COST. IN THIS WORK, TWO APPROACHES BASED ON THE SOL-GEL PROCESS WILL BE CARRIED OUT TO FABRICATE LARGE AREA OF SILVER HALIDE PHOTOCHROMIC GLASS COATINGS ON THE FIELD EQUIPMENT. THE COST OF FABRICATION WILL BE ESTIMATED AND EXPECTED TO BE LOW WHILE PRODUCIBILITY IS EXPECTED TO BE HIGH SINCE THE SOL-GEL PROCESS HAS BEEN APPLIED TO COMMERCIALLY FABRICATE VARIOUS LARGE AREA COATINGS ON GLASSES. IN THIS PROJECT, WE WILL DO SYSTEMATIC INVESTIGATIONS ON THE PROCESSING TO OPTIMIZE THE PROPERTIES AND LOWER COST. ANTICIPATED BENEFITS: THE SUCCESS OF THIS PROPOSED WORK WILL INTRODUCE AN ALTERNATIVE APPROACH TO MAKE THE PHOTOCHROMIC ARTICLES AT LOW COST. THE PHOTOCHRONMIC COATINGS ARE APPLIED NOT ONLY ON FIELD EQUIPMENT BUT MORE IMPORTANTLY ON GLASS WINDOW PANES. THE LATTER APPLICATION WILL BE BENEFICIAL FOR ENERGY CONSERVATION.