You may find that superscript and subscript text does not appear as expected in your published presentation if you are using PowerPoint 2010.
This is a known issue. You can work around it by grouping the affected text box with another object on the slide. Here's how:
- Select the text box that contains the superscript or subscript text.
- Press and hold the CTRL key, and click on another object on the slide to also select it. (You can select an existing object, or add a new shape to the slide specifically for this purpose.)
- Press CTRL+G to group both objects.
If you do not want the additional shape to appear in your published output, you can remove the fill color and line color, or you can drag the shape off the slide. Either method will essentially make the additional shape invisible in your published presentation.