Give the chemical reaction for the preparation of a borax bead.

(N/A) $Na_{2}B_{4}O_{7} \cdot 10H_{2}O \xrightarrow{\Delta} Na_{2}B_{4}O_{7} + 10H_{2}O$
$Na_{2}B_{4}O_{7} \xrightarrow{\Delta} 2NaBO_{2} + B_{2}O_{3}$
The mixture of $NaBO_{2}$ (sodium metaborate) and $B_{2}O_{3}$ (boric anhydride) forms a transparent,glassy bead known as the borax bead.