As for your ultimate goal of making the button change appearance, you can go two routes:
Use the SVG you are making with the desired text to export two versions of the image to PNG format: one with, and one without the glowing. Then use the onmouseover attribute for Javascript in the HTML to switch between the two on hover.
Use the actual SVG in the webpage, and use onmouseover to simply trigger a change in the way the SVG is styled. Inkscape can help you with this, but since I have not used this functionality I cannot say how.