"Filters can also be applied to the DIV and SPAN elements as well, but they must have an explicit height and width or have a 'position' property set to absolute."
Try something like this:
<p><SPAN ID="glow" STYLE="position:absolute; filter:glow(color=green,strength=5)">Glowing Text</span> <span style="padding-left:100px;">BleBleBle</span></p>
These methods both seem like hacks to me though. Depending on your desired result, you might also try using 2 div's combined with CSS-P for the glowing/non-glowing text.
<p><SPAN ID="glow" STYLE="height:10px; width:100px; filter:glow(color=green,strength=5)">Glowing Text</span> BleBleBle</p>