Preparation Research Of Quartz Glass Used For Optical Fiber Preform By Sol Gel Method

Optical fiber preform(optical preform) is the core technology in the industryof optical fiber manufacturing, and also is the profit core in the opticalcommunication industry. For reducing the cost of optical fiber, TEOS and H2Owere selected as raw material, HCl and NH3·H2O as catalyst, CH3NO andethylene glycol as anti-cracking agent to prepare the quartz glass dry gel used foroptical fiber preform by sol-gel method in the condition of different systems(withmiscible agent system and without agent system). The samples under theoptimum proportion were sintered. This paper mainly researched on the effect ofmiscible agent, catalyst, anti-cracking agent and heat treatment process on thecracking property of SiO2fiber optical preform. The XRD, FT-IR, SEM and EDSwere used to study the phase structure, microstructure, surface crack andchemical constituents of the samples.The quartz dry gel was prepared by16groups of samples in no miscibleagent system and27groups in miscible agent system. The dry gel was tested withthe gel time, transparency and anti-cracking as performance index. The XRD andEDS test indicated that the samples’ microstructures were amorphous and themain chemical constituents were Si and O. The results show that the TEOS andH2O can be uniformly mixed with vigorous stirring and water increasing withoutmiscible agent and also can be mixed to molecular level when the C2H5OH wasused as miscible agent. The hydrolysis rate of TEOS will increase with theincreasing of HCl and the transparency will decrease when the hydrochloridereaches a fixed value. Both CH3NO and ethylene glycol can play a role of anti-cracking agent. In no miscible agent system, the optimal capability parameter isTEOS: H2O: HCl: HOCH2CH2OH=1:30:0.7:1and TEOS: C2H5OH: H2O:Catalyst: CH3NO=1:6:8:0.06:0.1. The best heating processing technology was confirmed by the results of TGand FT-IR test: best reaction temperature was50℃, best drying temperature was75℃， during the sintering process, the dry gel should stay heat warm attemperature180℃,200℃and330℃in order to remove impurity solvent. Thetemperature should be risen slowly in order to prevent stress concentration. Thefinal sintering temperature was900℃.