These glasses are made of pure titanium and are very light.
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钛 has the metal radical 钅 (gold/metal) on the left and 太 (tài, great/too) on the right, which also gives the pronunciation. A 'great metal' - titanium is indeed known for its strength.
Metal radical on the left - the side-form of 金, the indexing radical. Modern element-name characters for metals all wear this radical: 铁 iron, 铜 copper, 银 silver, 铝 aluminium, 钨 tungsten. The radical labels 钛 as a metallic element on sight.
Right side 太 supplies the sound tài directly - a clean Mandarin loan matching the first syllable of 'titanium.' This is the textbook strategy for naming new elements: pick a 钅 radical and bolt on the closest-sounding character. 太 carries no semantic weight here.
