| 摘要 |
This invention is concerned with spontaneous opal glasses wherein sodium fluoride (NaF) and strontium fluoride (SrF2) constitute the predominant opacifying phases. More specifically, the opal glasses of the instant invention have compositions within the Na2O-SrO-Al2O3-SiO2-F field and exhibit a dense white appearance, a softening point above 755 DEG C., a strain point in excess of 500 DEG C., a coefficient of thermal expansion (0 DEG -300 DEG C.) in excess of 65 DEG x 10-7/ DEG C., and satisfactory resistance to weathering and dishwasher environments.
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