MODIFYING THE SURFACE OF ALKALI SILICATE MEDICAL GLASSES.

With the aim of showing the operational reliability of articles with a modified surface, the authors studied the chemical stability during multiple treatments in an autoclave with an increase in the dwell time. It was established that even after a 12 h dwell in the autoclave the chemical stability of the articles with a modified surface remains higher than that of the NS-2 borosilicate articles which had not been treated; the sigma //a//v of these was 7. 93 multiplied by (times) 10**31 **2mg of Na//2O. This is confirmed by the change in the pH of the distilled water contained in the articles with the modified surface; these articles were rapidly aged in accordance with the Instructions of the Ministry of Health of the USSR for carrying out work on the determination of the acceptable lifetime of medicinal media based on a rapid-ageing method at an enhanced temperature (57 days storage of the preparations at 70 degree C corresponds to 5 years under normal conditions). The criterion of the stability of chemical stability of the articles was the change in the pH of distilled water stored in them compared with the values given in State Standard 10782-77 ( less than equivalent to 1. 7).