function projtheme() {
var proj_title = document.getElementById("ring_1");
    proj_title.style.animation = "none";
    proj_title.style.WebkitAnimation = "none";
    proj_title.style.transform = "rotate(720deg)";
        proj_title.style.WebkitTransform = "rotate(720deg)";
        proj_title.style.opacity = "0.1";
}

function projtheme_exit() {

    var proj_title = document.getElementById("ring_1");
    proj_title.style.animation = "spin_cw 60s linear infinite";
    proj_title.style.WebkitAnimation = "spin_cw 60s linear infinite";
    proj_title.style.transform = "rotate(0deg)";
    proj_title.style.WebkitTransform = "rotate(0deg)";
    proj_title.style.opacity = "0.6";
}

<span id="projbtn" onmouseout="projtheme_exit();" onmouseover="projtheme();"></span>

#ring_1{
    position: absolute;
    top: 50%;
    left: 50%;

    margin-top: -160px;
    margin-left: -150px;

    opacity: 0.6;

    display:block;

    animation: spin_cw 60s linear infinite;
    -webkit-animation: spin_cw 60s linear infinite;

    transition: all 0.5s ease;

}